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1
Almosni, Samy. "Growth, structural and electro-optical properties of GaP/Si and GaAsPN/ GaP single junctions for lattice-matched tandem solar cells on silicon." Thesis, Rennes, INSA, 2015. http://www.theses.fr/2015ISAR0010/document.
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Cette thèse se concentre sur la fabrication de cellule solaire IIIN- V sur substrat de GaP (001) et sur la croissance de couche de GaP sur Si (001). Le but est de réaliser des cellules solaires hautes efficacité sur un substrat à faible coût afin de les intégrer dans des centrales solaire photovoltaïque sous concentration. Les principaux résultats obtenus montrent : - L’importance de l’utilisation d’AlGaP en tant que couche de prénucléation pour annihiler les parois d’antiphase à l’interface GaP/ Si (néfaste pour les propriétés optoélectroniques des dispositifs) - De nombreuses similitude entre la croissance de GaAsN et de GaPN ce qui permet d’élaborer une stratégie afin d’optimiser les propriétés optoélectroniques du GaAsPN - De fortes corrélations entre les propriétés optique et éléctriques dans les nitrures dilués - La réalisation préliminaire d’une cellule solaire monojonction sur GaP ayant un rendement encourageant de 2.25% considérant la faible épaisseur de l’absorbeur dans cette cellule (300 nm)This thesis focuses on optimizing the heterogeneous growth of IIIN- V solar cells on GaP (001) and GaP nanolayers on Si (001). The goal is to build high efficiency solar cells on low-cost substrate for the realization of concentrated photovoltaic powerplant. The main results shows: - AlGaP as prenucleation layer increase the annihilations of anti-phase boundaries at the GaP/Si interface (harmful for the electronic properties of the devices). - Similarities between the growth of GaAsN and GaPN giving strategies to improve the GaAsPN electrical properties - Clear correlations between the optical and electrical properties of dilute nitride solar cells, giving interesting tools to optimize the growth of those materials using optical measurements. - The realization of a GaAsPN solar cell on GaP with a yield of 2.25%. This results is encouraging given the thin GaAsPN absorber used in this cell
2
Vijh, Aarohi. "Triple Junction Amorphous Silicon based Flexible Photovoltaic Submodules on Polyimide Substrates." Connect to full text in OhioLINK ETD Center, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1122656006.
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Es, Firat. "Fabrication And Characterization Of Single Crystalline Silicon Solar Cells." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612363/index.pdf.
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The electricity generation using photovoltaic (PV) solar cells is the most viable and promising alternative to the fossil-fuel based technologies which are threatening world&rsquos climate. PV cells directly convert solar energy into electrical power through an absorption process that takes place in a solid state device which is commonly fabricated using semiconductors. These devices can be employed for many years with almost no degradation and maintenance. PV technologies have been diversified in different directions in recent years. Many technologies with different advantages have been developed. However, with more than %85 percent market share, Si wafer based solar cells have been the most widely used solar cell type. This is partly due to the fact that Si technology is well known from the microelectronic industry. This thesis is concerned with the production of single crystalline silicon solar cells and optimization of process parameters through the characterization of each processing step. Process steps of solar cell fabrications, namely, the light trapping by texturing, cleaning, solid state diffusion, lithography, annealing, anti reflective coating, edge isolation have all been studied with a systematic approach. Each sample set has been characterized by measuring I-V characteristics, quantum efficiencies and reflectance characteristics. The best efficiency that we reached during this study is 10.37% under AM1.5G illumination. This is below the efficiency values of the commercially available solar cells. The most apparent reason for the low efficiency value is the series resistance caused by the thin metal contacts. It is observed that the efficiency upon the reduction of series resistance effect is reduced. We have shown that the texturing and anti-reflective coating have a critically important effect for light management for better efficiency values. Finally we have investigated the fabrication of metal nanoparticles on the Si wafer for possible utilization of plasmonic oscillation in them for light trapping. The self assembly formation of gold nanoparticles on silicon surface has been successfully demonstrated. The optical properties of the nanoparticles have been studied
however, further and more detailed analysis is required.
4
Wilkins, Matthew M. "Design of Multi-junction Solar Cells on Silicon Substrates Using a Porous Silicon Compliant Membrane." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24096.
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A novel approach to the design of multi-junction solar cells on silicon substrates for 1-sun applications is described. Models for device simulation including porous silicon layers are presented. A silicon bottom subcell is formed by diffusion of dopants into a silicon wafer. The top of the wafer is porosified to create a compliant layer, and a III-V buffer layer is then grown epitaxially, followed by middle and top subcells. Due to the resistivity of the porous material, these designs are best suited to high efficiency 1-sun applications. Numerical simulations of a multi-junction solar cell incorporating a porous silicon compliant membrane indicate an efficiency of 30.7% under AM1.5G, 1-sun for low threading dislocation densities (TDD), decreasing to 23.7% for a TDD of 10^7 cm^-2.
5
Palaferri, Daniele. "Manufacturing and characterization of amorphous silicon alloys passivation layers for silicon hetero-junction solar cells." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5940/.
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Nel presente lavoro di tesi magistrale sono stati depositati e caratterizzati film sottili (circa 10 nm) di silicio amorfo idrogenato (a-Si:H), studiando in particolare leghe a basso contenuto di ossigeno e carbonio. Tali layer andranno ad essere implementati come strati di passivazione per wafer di Si monocristallino in celle solari ad eterogiunzione HIT (heterojunctions with intrinsic thin layer), con le quali recentemente è stato raggiunto il record di efficienza pari a 24.7% .
La deposizione è avvenuta mediante PECVD (plasma enhanced chemical vapour deposition). Tecniche di spettroscopia ottica, come FT-IR (Fourier transform infrared spectroscopy) e SE (spettroscopic ellipsometry) sono state utilizzate per analizzare le configurazioni di legami eteronucleari (Si-H, Si-O, Si-C) e le proprietà strutturali dei film sottili: un nuovo metodo è stato implementato per calcolare i contenuti atomici di H, O e C da misure ottiche. In tal modo è stato possibile osservare come una bassa incorporazione (< 10%) di ossigeno e carbonio sia sufficiente ad aumentare la porosità
ed il grado di disordine a lungo raggio del materiale: relativamente a quest’ultimo aspetto, è stata sviluppata una nuova tecnica per determinare dagli spettri ellisometrici
l’energia di Urbach, che esprime la coda esponenziale interna al gap in semiconduttori amorfi e fornisce una stima degli stati elettronici in presenza di disordine reticolare.
Nella seconda parte della tesi sono stati sviluppati esperimenti di annealing isocrono, in modo da studiare i processi di cristallizzazione e di effusione dell’idrogeno, correlandoli con la degradazione delle proprietà optoelettroniche.
L’analisi dei differenti risultati ottenuti studiando queste particolari leghe (a-SiOx e a-SiCy) ha permesso di concludere che solo con una bassa percentuale di ossigeno o carbonio, i.e. < 3.5 %, è possibile migliorare la risposta termica dello specifico layer, ritardando i fenomeni di degradazione di circa 50°C.
6
Davidson, Lauren Michel. "Strategies for high efficiency silicon solar cells." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5452.
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The fabrication of low cost, high efficiency solar cells is imperative in competing with existing energy technologies. Many research groups have explored using III-V materials and thin-film technologies to create high efficiency cells; however, the materials and manufacturing processes are very costly as compared to monocrystalline silicon (Si) solar cells. Since commercial Si solar cells typically have efficiencies in the range of 17-19%, techniques such as surface texturing, depositing a surface-passivating film, and creating multi-junction Si cells are used to improve the efficiency without significantly increasing the manufacturing costs. This research focused on two of these techniques: (1) a tandem junction solar cell comprised of a thin-film perovskite top cell and a wafer-based Si bottom cell, and (2) Si solar cells with single- and double-layer silicon nitride (SiNx) anti-reflection coatings (ARC).
The perovskite/Si tandem junction cell was modeled using a Matlab analytical program. The model took in material properties such as doping concentrations, diffusion coefficients, and band gap energy and calculated the photocurrents, voltages, and efficiencies of the cells individually and in the tandem configuration. A planar Si bottom cell, a cell with a SiNx coating, or a nanostructured black silicon (bSi) cell can be modeled in either an n-terminal or series-connected configuration with the perovskite top cell. By optimizing the bottom and top cell parameters, a tandem cell with an efficiency of 31.78% was reached.
Next, planar Si solar cells were fabricated, and the effects of single- and double-layer SiNx films deposited on the cells were explored. Silicon nitride was sputtered onto planar Si samples, and the refractive index and thicknesses of the films were measured using ellipsometry. A range of refractive indices can be reached by adjusting the gas flow rate ratios of nitrogen (N2) and argon (Ar) in the system. The refractive index and thickness of the film affect where the minimum of the reflection curve is located. For Si, the optimum refractive index of a single-layer passivation film is 1.85 with a thickness of 80nm so that the minimum reflection is at 600nm, which is where the photon flux is maximized. However, using a double-layer film of SiNx, the Si solar cell performance is further improved due to surface passivation and lowered surface reflectivity. A bottom layer film with a higher refractive index passivates the Si cell and reduces surface reflectivity, while the top layer film with a smaller refractive index further reduces the surface reflectivity. The refractive indices and thicknesses of the double-layer films were varied, and current-voltage (IV) and external quantum efficiency (EQE) measurements were taken. The double-layer films resulted in an absolute value increase in efficiency of up to 1.8%.
7
Lin, Derek Yun Tsung. "Integrating graphene and nanofibers with silicon to form Schottky junction solar cells." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43933.
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Since the development of the world’s first practical solar cell in 1954 at Bell Laboratories, researches have been conducted to increase solar cell efficiencies and lower the fabrication cost. Traditional Schottky junction solar cells suffer from the low transparency of metal films and increasing cost of indium tin oxide. In this thesis, p-type and n-type silicon Schottky junction solar cells are fabricated by integrating novel materials with silicon in an attempt to overcome these limitations.
The p-type solar cells integrate graphene and p-type silicon. Graphene is first synthesized using scotch tape exfoliation method, and then using chemical vapor deposition (CVD) of methane on copper foils to improve its quality. The CVD graphene growth system is custom built in our lab. Graphene films are optically and electrically characterized and solar cells are fabricated. Measured solar cell characteristics results are presented and reasons for the obtained parameters are discussed. Finally, methods for improving the solar cell performance are described.
The n-type solar cells are fabricated by depositing gold coated Polyacrylonitrile (PAN) nanofiber mesh on top of n-type silicon. Schottky junctions are formed where the nanofibers are in contact with silicon surface, and each junction contributes to the total current. The nanofibers are economically produced by electrospinning and coated with gold by sputtering. The solar cells are characterized and the results suggest this structure can be a promising candidate for photovoltaic application.
In addition to experimental work, we conduct numerical simulations of graphene based Schottky junction solar cells to identify possible future applications of graphene. Copper indium gallium diselenide, cadmium telluride, and amorphous silicon are chosen as the semiconductor bases because of their high absorption coefficient, high/tunable bandgap, and the possibility for economical fabrication as compared to single crystal silicon technology. The simulation is carried out using MATLAB with material properties obtained from textbooks and published literatures. The simulation results provide an estimate of the relevant photovoltaic parameters. It identifies graphene/p-type cadmium telluride as a potential Schottky junction solar cell that can achieve a conversion efficiency of 11.3%, if the graphene sheet resistance of 30 ohms/square and transmittance of 90% can be attained.
8
Lynch, Marianne Catherine. "Modelling and optimisation of single junction strain balanced quantum well solar cells." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/8479.
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In an attempt to find the optimum number of wells for maximum conversion efficiency a pair of otherwise identical strain balanced samples, one containing 50 wells and the other 65 wells have been characterised. The 65 well sample is found to possess a lower predicted efficiency than the 50 well sample, suggesting that the optimum well number lies between these values. Devices grown using tertiary butyl arsine (TBAs) are found to possess comparable conversion efficiencies to the control cells grown using arsine and slightly superior dark IV characteristics, indicating that TBAs may be substituted for arsine without loss of device efficiency and may even be beneficial to cell performance. Several fundamental refinements to the existing quantum efficiency model of are explored. Firstly, expressions for the strained band gaps are derived. A value for the conduction band offset is determined using the difference in energy between the heavy and light hole exciton peaks in low temperature photo current scans and found to be 0.55±0.03. The magnitude of the el-hhl exciton binding energy is also estimated from these scans and found to be in excellent agreement with the value obtained from a simple, parameterized expression for the exciton binding energy. Finally, an absolute calculation for the absorption coefficient is incorporated into the quantum efficiency model and values for the heavy and light hole in-planes masses are obtained. The model is found to underestimate the level of absorption in the intrinsic region by an amount consistent with estimates of the magnitude of the reflection from the back surface. The conversion efficiency of a sample predicted using SOL is compared to an independently obtained value. Good agreement is observed between the two results (25.3% and 25.7% for 317 suns AM1.5D). Additionally, an optimum structure for illumination by the AM1.5D spectrum was found to be a 120A well ofIno.lGaAs.
9
Al, ghzaiwat Mutaz. "Fabrication and study of solar cell modules based on silicon nanowire based radial junction solar cells." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX101/document.
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Dans cette thèse, nous avons utilisé un réacteur de dépôt chimique en phase vapeur assisté par plasma (PECVD) à basse température afin de fabriquer des minimodules à base de cellules solaires à jonction radiale (RJ SiNWs) sur des substrats de verre de 5x5 cm² en employant la gravure laser pour la mise en série des cellules.Nous avons utilisé une couche de 600 nm d’épaisseur de dioxyde d’étain dopée au fluor (FTO) déposée sur du verre sodocalcique (SLG). La couche de FTO sert à la fois de contact arrière pour le module et de source de catalyseur Sn une fois la couche de FTO réduite par un plasma de H2. Ensuite, on fait croître des SiNW dopés p par le procédé Vapor-Liquid-Solid (VLS) assisté par plasma, suivi d’un dépôt d’une couche de Si intrinsèque a-Si:H et d’une couche de Si dopée n µc-SiOx:H, afin d’obtenir une cellule solaire à jonction radiale PIN. Nous avons obtenu une efficacité énergétique de 6.3 % avec une surface active de 0.126 cm². C’est à notre connaissance l’efficacité la plus élevée obtenue en utilisant une couche de FTO comme source de catalyseur Sn.La gravure laser a été utilisée pour retirer localement des couches minces dans l’objectif de fabriquer des minimodules solaires. Grâce à la gravure laser, une connexion monolithique en série entre les cellules solaires à jonction radiale adjacentes a pu être accomplie. Dans cette thèse, la gravure laser a servi à retirer localement la couche de FTO ainsi que les RJ SiNWs, étapes appelées respectivement P1 et P2. On dépose ensuite une couche transparente d’oxyde d’indium-étain (ITO), servant de contact avant, par pulvérisation cathodique (étape P3), et on procède à la séparation en bandes par la technique « lift-off ». Nous avons mené une étude détaillée de l’étape P2 de gravure obtenue par un laser vert (532 nm) et IR (1064nm). La puissance du laser a un impact direct sur l’ablation des RJ SiNWs, et peut aussi endommager le contact arrière de la cellule. Nous avons déterminé que le laser vert entraîne une fonte partielle de matériau sur les bords de la zone gravée, contrairement au laser IR qui produit des gravures de meilleure qualité. La cartographie Raman des zones gravées permet une analyse des matériaux dans la zone étudiée, et a donné des indications sur la composition des résidus laissés par les impulsions laser. Nous avons démontré que l’utilisation du laser IR pour l’étape P2 de gravure est préférable. Elle permet d’avoir des connexions en série de haute qualité entre les cellules.Enfin, le mini-module optimisé de 10 cm² à base de RJ SiNWs a atteint un rendement de conversion énergétique de 4.37 % avec une puissance générée de 44 mW, grâce à l’amélioration de l’étape P2 et de l’impression par jet d’encre d’une grille dense d’Ag. À notre connaissance, cette puissance générée est la plus élevée rapportée pour des modules solaires à base de cellules à jonction radialeIn this thesis, we have used a low-temperature plasma-enhanced chemical vapor deposition (PECVD) reactor to fabricate Si nanowire radial junction solar mini-modules on 5x5 cm2 glass substrates with the assistance of the laser scribing technique for the series connection of the cells.We have used fluorine-doped tin oxide (FTO) deposited on soda-lime glass substrates (SLG) as a back contact as well as the source of the Sn catalyst which was formed by a direct reduction of FTO using a H2 plasma. Subsequently, p-type SiNWs were grown using plasma-assisted vapor liquid solid (VLS) process, followed by the deposition of intrinsic a-Si:H and n-type µc-SiOx:H layers to achieve pin radial junction solar cells. We have obtained an energy conversion efficiency of 6.3 % with an active area of solar cells of 0.126 cm2, which is to our knowledge, the highest efficiency obtained based on FTO layers as a source of Sn catalyst.Laser scribing was used to perform a selective removal of thin-film materials in order to fabricate minimodules. With laser scribing, a monolithic series connection between adjacent RJ SiNW solar cells on the same glass substrate was achieved. In particular, the laser scribing system has been used to perform selective removal of FTO thin-film and RJ SiNWs, which are commonly known as step P1 and P2, respectively, and to perform a final scribe to isolate the active region from the rest of the substrate. The transparent top ITO contact was sputtered and cell stripes were defined using the lift-off technique (step P3).We have carried out a detailed study of the P2 laser scribe obtained with either green (532 nm) or IR (1064 nm) laser setups. The power of the laser has to be controlled as it has a direct impact on the removal of SiNW RJs and it can damage the underneath FTO contact. We have found that the scribing using a green laser produces a partial melting outside the scribed spots, unlike the IR laser which provides a cleaner scribing and less crystallized material at the edges of scribed spots. Mapping of the scribed spots using Raman spectroscopy allowed analyzing the material composition within the scanned area inside the craters left by the laser pulses. We have demonstrated that the use of the IR laser is preferable for P2 scribing because it can provide a high-quality series connection between cells.Finally, the optimized 10 cm2 SiNW RJ mini-module has reached an energy conversion efficiency of 4.37 % with power generation of 44 mW, thanks to the improved P2 laser scribing and the dense Ag grid printed using the ink-jet method. This performance represents, to the best of our knowledge, the highest reported power generation for silicon nanowire-based solar modules on glass substrates
10
Stoke, Jason A. "Spectroscope ellipsometry analysis of the component layers of hydrogenated amorphous silicon triple junction solar cells /." Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1222351957.
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Thesis (M.S.)--University of Toledo, 2008.Typescript. "Submitted as partial fulfillment of the requirements for Master of Science in Physics." "A thesis entitled"--at head of title. Bibliography: leaves 129-133.
11
Shim, Jae Won. "Study of charge-collecting interlayers for single-junction and tandem organic solar cells." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51820.
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A hole-collecting interlayer layer for organic solar cells, NiO, processed by atomic layer deposition (ALD) was studied. ALD-NiO film offered a novel alternative to efficient hole-collecting interlayers in conventional single-junction organic solar cells. Next, surface modifications with aliphatic amine group containing polymers for use as electron-collecting interlayers were studied. Physisorption of the polymers was found to lead to large reduction of the work function of conducting materials. This approach provides an efficient way to provide air-stable low-work function electrodes for organic solar cells. Highly efficient inverted organic solar cells were demonstrated by using the polymer surface modified electrodes. Lastly, charge recombination layers of the inverted tandem organic solar cells were studied. Efficient charge recombination layers were realized by using the ALD and the polymer surface modification. The charge recombination layer processed by ALD provided enhanced electrical and barrier properties. Furthermore, the polymer surface modification on the charge recombination layers showed large work function contrast, leading to improved inverted tandem organic solar cells. The inverted tandem organic solar cells with the new charge recombination layer showed fill factor over 70% and power conversion efficiency over 8%.
12
Mahajumi, Abu Syed. "Type-II gallium antimonide quantum dots in gallium arsenide single junction solar cells." Thesis, Lancaster University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.658211.
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The novel idea of GaSb quantum dots (QDs)1 quantum rings (QRs) stacked layers single junction solar cells have been investigated for the examination and enhancement of the infrared photo response. Initially the investigation used photoluminescence to probe the optical properties of a type-II material interface between GaSb/GaAs using optimum growth temperature for QDs/QRs with two different growth modes (Stranski-Krastanow (SK) and exchange growth); and two different GaSb deposition thickness (1.5ML and 2.IML). The photoluminescence spectra of the stacked epilayers confirmed that the dominant radiative recombination mechanism was band-to-band in the GaSb QDs/QRs stacked layers. Excellent structural quality is observed in each sample with no threading dislocations (by Transmission Electron Microscopy (TEM)). The composition of the QRs is close to 100 % GaSb with high purity GaAs centres. The ring density per layer is approximately 1010 rings/cm2 with no significant variation in size or density in the separate layers. II Rapid thermal annealing (RTA) has been used to tailor the optical properties of 10-layer stacks of type-II GaSb self-assembled QDs and QRs embedded within GaAs grown by molecular beam epitaxy. An increase in PL emission intensity and a blue shift in peak energy in both types of QD stacks were observed, along with changes in the activation energy for PL quenching. These effects were attributed to Sb-As intermixing and size effects with corresponding changes in the band structure and an increase in the oscillator strength associated with the transformation towards type-I behaviour. It has been concluded that postgrowth rapid thermal annealing can be used to tune the spectral response and control carrier recombination and escape properties of stacked GaSb QD for more effective use in devices such as solar cells and lasers. The final part of the investigation examined the properties of multi-layer QDs/QRs single junction solar cells (SC) to obtain an understanding of the operation and characteristics of the devices. Three kinds of solar cells were fabricated; one is intrinsic layer with ? layers of QDs/QRs, another comprises 10 layers and the final one is control cells (without QDs/QRs).
13
Dai, Letian. "Silicon nanowire solar cells with μc-Si˸H absorbers for tandem radial junction devices." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS303.
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Dans cette thèse, nous avons fabriqué des cellules solaires à jonction radiale en nanofils de silicium avec du silicium microcristallin hydrogéné (µc-Si:H) comme absorbeur, par dépôt chimique en phase vapeur assisté par plasma à basse température (PECVD). Pour contrôler la densité de nanofils sur les substrats, nous avons utilisé des nanoparticules (NP) de dioxyde d'étain (SnO₂) d'un diamètre moyen de 55 nm, disponibles dans le commerce, comme précurseur du catalyseur Sn pour la croissance des nanofils de silicium. La distribution des nanoparticules de SnO₂ sur le substrat a été contrôlée par centrifugation et dilution du colloïde de SnO₂, en combinaison avec la fonctionnalisation du substrat. Par la suite, le SnO₂ est réduit en Sn métallique après le traitement par plasma de H₂, suivi de la croissance, par la technique vapeur-liquide-solide (VLS) assistée par plasma, de nanofils de Si sur lesquels sont déposées les couches P, I et N constituant les cellules solaires à jonction radiale. Nous avons atteint un taux de croissance élevé des nanofils de Si, jusqu'à 70%, avec une très large gamme de densité, de 10⁶ à 10⁹ /cm². Comme approche supplémentaire de contrôle de la densité des nanofils, nous avons utilisé du Sn évaporé comme précurseur du catalyseur Sn. Nous avons étudié l'effet de l'épaisseur de Sn évaporé, l'effet de la durée du traitement au plasma de H₂ et l'effet du débit de gaz H₂ dans le dans le mélange de précurseurs, sur la densité des nanofils. L'ellipsométrie spectroscopique in-situ (SE) a été utilisée pour contrôler la croissance des nanofils et le dépôt des couches de µc-Si:H sur les SiNWs. En combinant les résultats de in-situ SE et de microscopie électronique à balayage, une relation entre l'intensité du signal de SE pendant la croissance et la longueur et la densité des nanofils a été démontrée, ce qui permet d'estimer ces paramètres en cours de croissance. Nous avons réalisé une étude systématique des matériaux (couches intrinsèques et dopées de type n ou p de µc-Si:H, couches dopées d'oxyde de silicium microcristallin hydrogéné, µcSiOx:H) et des cellules solaires obtenues dans deux réacteurs à plasma appelés "PLASFIL" et "ARCAM". Les épaisseurs de revêtement sur substrat lisse et sur les nanofils ont été déterminées et nous avons obtenu une relation linéaire entre les deux, ce qui permet de concevoir un revêtement conforme sur les nanofils pour chaque couche avec une épaisseur optimale. Les paramètres des nanofils et des matériaux, affectant la performance des cellules solaires à jonction radiale, ont été systématiquement étudiés, les principaux étant la longueur et la densité des nanofils, l'épaisseur de la couche intrinsèque de µc-Si:H, l'utilisation de µc-SiOx:H et le réflecteur arrière en Ag. Enfin, avec les cellules solaires à jonction radiale en nanofils de silicium optimisées utilisant le µc-Si:H comme absorbeur, nous avons atteint un rendement de conversion de l'énergie de 4,13 % avec Voc = 0,41 V, Jsc = 14,4 mA/cm² et FF = 69,7%. Cette performance est supérieure de plus de 40 % à l'efficacité record de 2,9 % publiée précédemmentIn this thesis, we have fabricated silicon nanowire (SiNW) radial junction solar cells with hydrogenated microcrystalline silicon (μc-Si:H) as the absorber via low-temperature plasma-enhanced chemical vapor deposition (PECVD). To control the density of NW on the substrates, we have used commercially available tin dioxide (SnO₂) nanoparticles (NPs) with an average diameter of 55 nm as the precursor of Sn catalyst for the growth of SiNWs. The distribution of SnO₂ NPs on the substrate has been controlled by centrifugation and the dilution of the SnO₂ colloid, combined with the functionalization of the substrate. Subsequently, SnO₂ is reduced to metallic Sn after the H₂ plasma treatment, followed by the plasma-assisted vapor-liquid-solid (VLS) growth of SiNWs upon which the P, I and N layers constituting the radial junction solar cells are deposited. We have achieved a high yield growth of SiNWs up to 70% with a very wide range of NW density, from 10⁶ to 10⁹ /cm². As an additional approach of controlling the density of SiNWs we have used evaporated Sn as the precursor of Sn catalyst. We have studied the effect of the thickness of evaporated Sn, the effect of duration of H₂ plasma treatment and the effect of H₂ gas flow rate in the plasma, on the density of SiNWs.In-situ spectroscopic ellipsometry (SE) was used for monitoring the growth of SiNWs and the deposition of the layers of μc-Si:H on SiNWs. Combining in-situ SE and SEM results, a relationship between the intensity of SE signal and the length and the density of SiNWs during the growth was demonstrated, which allows to estimate the density and the length of SiNWs during the growth. We have carried out a systematic study of materials (intrinsic, p-type,n-type µc-Si:H and µcSiOx:H doped layers) and solar cells obtained in two plasma reactors named “PLASFIL” and “ARCAM”. The thicknesses of coating on the flat substrate and on the SiNWs have been determined with a linear relation which helps to design a conformal coating on SiNWs for each layer with an optimal thickness. The parameters of the SiNWs and the materials, affecting the performance of radial junction solar cells, have been systematically studied, the main ones being the length and the density of SiNWs, the thickness of intrinsic layer of μc-Si:H on SiNWs, the use of the hydrogenated microcrystalline silicon oxide (μc-SiOx:H) and the back reflector Ag. Finally, with the optimized silicon nanowire radial junction solar cells using the μc-Si:H as the absorber we have achieved an energy conversion efficiency of 4.13 % with Voc = 0.41 V, Jsc = 14.4 mA/cm² and FF = 69.7%. This performance is more than 40 % better than the previous published record efficiency of 2.9 %
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Harris, John Michael. "The Nature of Single-Wall Carbon Nanotube-Silicon Heterojunction Solar Cells." Diss., North Dakota State University, 2015. http://hdl.handle.net/10365/24876.
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Since their inception in 2007, nanotube-silicon heterojunction solar cells have experienced rapid improvement due to the diligent work of several research groups. These devices have quickly reached a point where they might begin to possibly compete with current well-established silicon solar technologies; however the development of industrial-scale nanotube synthesis and purification capabilities remains problematic.
Although there has been significant recent progress in improving performance, the precise classification of nanotube-silicon heterojunctions has remained ambiguous. In this thesis, I use type, chirality and length purified single-wall carbon nanotubes to clarify the nature of this particular class of solar cell. The junctions that I assembled were made from freestanding nanotube sheets that showed remarkable stability in response to repeated crumpling and folding during fluid processing, which suggests that the films could be well suited to flexible device platforms. Despite modest ideality factors, the best diodes created in this study met or exceeded state-of-the-art device characteristics, but with a surprising lack of any significant dependence on sample type. The data further suggest that these devices might be simultaneously categorized as either Schottky or p-n junctions. More importantly, the results of this study demonstrate the manner in which band-gap engineering can optimize these devices while emphasizing the important role of the junction morphology.NSF EPS-0814442
NSF CMMI-0969155
DOE DE-FG36-08GO88160
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Haase, Felix [Verfasser]. "Loss analysis of back-contact back-junction thin-film monocrystalline silicon solar cells / Felix Haase." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2013. http://d-nb.info/1042066647/34.
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Stoke, Jason A. "Spectroscopic ellipsometry analysis of the component layers of hydrogenated amorphous silicon triple junction solar cells." University of Toledo / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1222351957.
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Woehl, Robert [Verfasser]. "All-Screen-Printed Back-Contact Back-Junction Silicon Solar Cells with Aluminum-Alloyed Emitter / Robert Woehl." München : Verlag Dr. Hut, 2012. http://d-nb.info/1023435179/34.
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O'Donnell, Benedict. "Plasma grown silicon nanowires catalysed by post-transition metals and applications in radial junction solar cells." Palaiseau, Ecole polytechnique, 2012. https://pastel.hal.science/docs/00/76/15/66/PDF/ODonnell_-_PhD_2012.pdf.
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Cette thèse présente des cellules solaires en silicium deposées par plasma dans lesquelles la lumière est piégée par un réseau désorganisé de nanofils de silicium. Le dépôt sous vide des nanofils permet de contourner les étapes de texturation de substrat typiquement requises pour augmenter le parcours moyen des photons dans les cellules solaires en couches minces classiques. Des gouttes d'étain et d'indium servant à catalyser la croissance de ces nanofils ont été déposées et disposées sous vide sur des substrats d'oxide trasparent conducteur. Des agencements de gouttes métalliques aux diamètres et densités couvrant plusieurs ordres de grandeur ont été obtenus en optimisant les matériaux et les conditions de dépôt utilisés. En comparant l'aptitude de différents métaux à catalyser la croissance de nanofils de silicium, des distinctions majeures ont été établies entre les métaux de transition et Sn, In, Bi, Ga, Pb et Al. Le cas des nanofils de silicium catalysés par des gouttes d'étain a été étudié en profondeur. Des réseaux désorganisés de nanofils dopés de type P ont été recouverts de couches de silicium amorphe hydrogéné intrinsèque et dopés N, ainsi que d'une couche d'oxide d'ITO pour former des réseaux de 107 jonctions PIN radiales couvrant des surfaces de 3,1 mm². Ces cellules présentent des tensions à circuit ouvert de 0,8 V et des courants de court-circuit de 13 mA/cm² bien qu'elles soient entièrement déposées par des étapes sous vide sur des substrats non texturésIn this thesis, disordered arrays of vertical silicon nanowires are used to trap light in PECVD-deposited silicon solar cells. The abrupt surface which they present can absorb light efficiently and be manufactured in the same vacuum run as the other layers of the cell, offering the prospect of dispensing with the additional fabrication steps conventionally required to texture the substrates of thin-film photovoltaics. Drops of liquid tin and indium, designed to catalyze the growth of silicon nanowires, were deposited and rearranged on transparent conducting oxide substrates under vacuum to obtain metal drop configurations with diameters and densities spanning several orders of magnitude. In discussing the suitability of different metals to catalyze the growth of silicon nanowires, we have highlighted distinctions between the behavior of transition and non-transition metals for vapor-liquid-solid growth and studied in particular the case of silicon nanowires catalyzed by tin. Nanowires doped P-type with the appropriate morphology were covered in conformal layers of intrinsic and N-type hydrogenated amorphous silicon, and an indium-tin-oxide electrical contact to produce networks of 107 radial PIN junctions connected over areas of 3. 1 mm². Optimizing the fabrication process of these devices has led to open-circuit voltages of 0. 8 V and short-circuit currents of 13 mA/cm². The cells are deposited over untextured substrates using techniques which are compatible with a single pump-down process. Their ability to trap light rivals that of established texturing techniques and their performance comes close to that of planar PIN structures
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Reichel, Christian [Verfasser]. "Decoupling Charge Carrier Collection and Metallization Geometry of Back-Contacted Back-Junction Silicon Solar Cells / Christian Reichel." München : Verlag Dr. Hut, 2012. http://d-nb.info/1022535285/34.
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Tournet, Julie. "III-Sb-based solar cells and their integration on Si." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS003/document.
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Les matériaux III-Sb ont prouvé leur potentiel pour la réalisation de composants opto-électroniques dans des domaines aussi variés que les télécommunications ou l'environnement. Cependant, ils restent une filière quasi-inexplorée pour les systèmes photovoltaïques classiques. Dans ce projet de recherche, nous voulons démontrer que les composants à base d'antimoniures sont des candidats prometteurs pour des cellules solaires à haute efficacité et bas coût. Leurs avantages sont multiples : non seulement offrent-ils un large panel d'alliages accordés en maille et des jonctions tunnel à basse résistivité, mais ils permettent aussi une croissance directe sur substrat de Si. Nous étudions donc les briques élémentaires d'une cellule solaire multi-jonction intégrée sur Si. Tout d'abord, nous développons la croissance et fabrication de cellules homo-épitaxiales en GaSb. Les caractéristiques tension-intensité (J-V) mesurées sont proches de l'état de l'art avec une efficacité sous un soleil de 5.9 %. Puis, nous intégrons une cellule à simple jonction GaSb sur un substrat de Si par épitaxie par jet moléculaire (EJM). Les analyses de diffraction X (DRX) et de microscopie à force atomique (AFM) montrent des propriétés de structure et morphologie proches de celles reportées pour des buffers métamorphiques similaires dans la littérature. Nous adaptons alors la configuration de la cellule pour éviter la haute densité de défauts à l'interface GaSb/Si. La cellule hétéro-épitaxiale a une efficacité réduite de 0.6 %. Ce résultat est néanmoins proche des dernières avancées sur les cellules GaSb sur GaAs, et ce, malgré un désaccord de maille plus important. Enfin, nous étudions l'épitaxie d'AlInAsSb. Cet alliage pourrait en théorie atteindre une grande gamme d'énergies de bande interdite tout en restant accordé sur GaSb. Néanmoins, il souffre d'une lacune de miscibilité importante, le rendant sujet à la ségrégation de phase. Il n'y a que peu de mentions de l'AlInAsSb dans la littérature, et toutes rapportent des conditions de croissance instables et des énergies de bande interdite plus basses qu'attendues. Nous réussissons à produire des couches de bonne qualité d'AlInAsSb dont la composition en Al varie de 0.25 à 0.75 et ne présentant aucun signe macroscopique de décomposition de phase. Toutefois, l'observation au microscope à transmission électronique (TEM) révèle des fluctuations de composition nanométriques. Les données de photoluminescence (PL) sont étudiées pour déterminer les propriétés électroniques de l'alliage. Les mesures d'efficacité quantique (QE) montrent que la sous-cellule du haut limite la performance de la cellule tandem. Des modélisations numériques des courbes J-V et QE sont utilisées pour identifier des pistes d'amélioration pour chaque brique élémentaireIII-Sb materials have demonstrated their potential for multiple opto-electronic devices, with applications stretching from communications to environment. However, they remain an almost unexplored segment for classical photovoltaic systems. In this research, we intend to demonstrate that III-Sb-based devices are promising candidates for high-efficiency, low-cost solar cells. Their benefits are two-fold: not only do they offer a wide range of lattice-matched alloys and low-resistivity tunnel junctions, but they also enable direct growth on Si substrates. We thus investigate the building blocks of a GaSb-based multi-junction solar cell integrated onto Si. First, we develop the photovoltaic growth and processing by fabricating homo-epitaxial GaSb cells. Intensity-voltage (J-V) measurements approach the state of the art with 1-sun efficiency of 5.9%. Then, we integrate a GaSb single-junction cell on a Si substrate by molecular beam epitaxy (MBE). X-ray diffraction (XRD) and atomic force microscopy (AFM) analysis show structural and morphological properties close to the best reported in the literature for similar metamorphic buffers. We further adapt the cell configuration to circumvent the high defect density at the GaSb/Si interface. The heteroepitaxial cell results in a reduced efficiency of 0.6%. Nevertheless, this performance is close the most recent advancements on GaSb heteroepitaxial cells on GaAs, despite a much larger mismatch. Last, we investigate the epitaxy of AlInAsSb. This alloy could in theory reach the widest range of bandgap energies while being lattice-matched to GaSb. However, it presents a large miscibility gap, making it vulnerable to phase segregation. AlInAsSb only counts few experimental reports in the literature, all referring to unoptimized growth conditions and abnormally low bandgap energies. We successfully grow good-quality layers with Al composition x_{Al} ranging from 0.25 to 0.75, showing no macroscopic sign of decomposition. Yet, transmission electron microscopy (TEM) observations point to nanometric fluctuations of the quaternary composition. Photoluminescence (PL) data is studied to determine the alloy's electronic properties. We eventually propose and fabricate a tandem cell structure, resulting in 5.2% efficiency. Quantum Efficiency (QE) measurements reveal that the top subcell is limiting the tandem performance. Numerical fits to both J-V and QE data indicate improvement paths for each building block
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Korostyshevsky, Aaron. "Characterization of Radiation Damage in Multi-Junction Solar Cells Using Light-Biased Current Measurements." Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1224614484.
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Thesis (M.S.)--University of Toledo, 2008.Typescript. "Submitted as partial fulfillments of the requirements for the Master of Science Degree in Physics." "A thesis entitled"--at head of title. Bibliography: leaves 41-42.
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Woods, Michael D. "A comparative analysis of radiation effects on silicon, gallium arsenide, and GaInP2/GaAs/Ge triple junction solar cells using a 30 MeV electron linear accelerator." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion/02Sep%5FWoods.pdf.
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Anderson, Tom Harper. "Optoelectronic simulation of nonhomogeneous solar cells." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25892.
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This thesis investigates the possibility of enhancing the efficiency of thin film solar cells by including periodic material nonhomogeneities in combination with periodically corrugated back reflectors. Two different types of solar cell are investigated; p-i-n junctions solar cells made from alloys of hydrogenated amorphous silicon (a-Si:H) (containing either carbon or germanium), and Schottky barrier junction solar cells made from alloys of indium gallium nitride (InξGa1-ξN). Material nonhomogeneities are produced by varying the fractions of the constituent elements of the alloys. For example, by varying the content of carbon or germanium in the a-Si:H alloys, semiconductors with bandgaps ranging from 1:3 eV to 1:95 eV can be produced. Changing the bandgap alters both the optical and electrical properties of the material so this necessitates the use of coupled optical and electrical models. To date, the majority of solar cell simulations either prioritise the electrical portion of the simulation or they prioritise the optical portion of the simulation. In this thesis, a coupled optoelectronic model, developed using COMSOL Multiphysics®, was used to simulate solar cells: a two-dimensional finite-element optical model, which solved Maxwell's equations throughout the solar cells, was used to calculate the absorption of incident sunlight; and a finite-element electrical drift-diffusion transport model, either one- or two-dimensional depending on the symmetries of the problem, was used to calculate the steady state current densities throughout the solar cells under external voltage biases. It is shown that a periodically corrugated back reflector made from silver can increase efficiency of an a-Si:H alloy single p-i-n junction solar cell by 9:9% compared to a baseline design, while for a triple junction the improvement is a relatively meagre 1:8%. It is subsequently shown that the efficiency of these single p-i-n junction solar cells with a back reflector can be further increased by the inclusion of material nonhomogeneities, and that increasing the nonhomogeneity progressively increases efficiency, especially in thicker solar cells. In the case of InξGa1-ξN Schottky barrier junction solar cells, the gains are shown to be even greater. An overall increase in efficiency of up to 26:8% over a baseline design is reported.
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Hilmersson, Christina. "Detection of Cracks in Single-Crystalline Silicon Wafers Using Impact Testing." Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3789.
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This thesis is about detection of cracks in single-crystalline silicon wafers by using a vibration method in the form of an impact test. The goal to detect cracks from vibration measurements introduced by striking the silicon wafer with an impact hammer. Such a method would reduce costs in the production of solar cells. It is an inexpensive, relatively simple method which if commercialized could be used as an efficient in-line production quality test.
A hammer is used as the actuator and a microphone as the response sensor. A signal analyzer is used to collect the data and to compute frequency response. Parameters of interest are audible natural frequencies, peak magnitudes, damping ratio and coherence.
The data reveals that there are differences in frequency between the cracked silicon wafers and the non-cracked silicon wafers. The resonant peaks in the defective wafers were not as sharp (i.e., lightly damped) and occurred at lower frequencies (i.e., lower stiffness) with a lower magnitude and a higher damping ratio. These differences could be used to detect damaged product in a solar cell production line.
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Wolf, Fabian Alexander [Verfasser], and Peter [Akademischer Betreuer] Pichler. "Modeling of Annealing Processes for Ion-Implanted Single-Crystalline Silicon Solar Cells / Fabian Alexander Wolf. Gutachter: Peter Pichler." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/1075832268/34.
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Surana, Kavita. "Towards silicon quantum dot solar cells : comparing morphological properties and conduction phenomena in Si quantum dot single layers and multilayers." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00647293.
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Le confinement quantique dans le silicium, sous forme de boîtes quantiques de silicium de diamètre 5 nm, permet de contrôler le bandgap et donc l'émission de lumière. Cette ingénierie du bandgap des nanocristaux de silicium est utile pour les applications photovoltaïques avancées et présente l'avantage de conserver la compatibilité avec les technologies silicium existantes. Ces boîtes quantiques peuvent aider à réduire les pertes par thermalisation dans une cellule solaire homo-jonction. Ce travail se concentre sur la fabrication à grande échelle des nanocristaux de silicium dans SiO2 en utilisant le Dépôt Chimique en Phase Vapeur assisté par Plasma (PECVD), suivi d'un recuit à haute température. Des monocouches sont comparées avec des multicouches pour les propriétés morphologiques, électriques et optiques et des dispositifs avec ces différents couches sont comparés. Dans le cas d'une structure monocouche, l'épaisseur de la couche contrôle l'organisation des nanocristaux et permet de mettre en évidence l'amélioration de la conductivité électrique, avec cependant une réponse optique faible. Les multicouches montrent un bandgap du Si augmentée et controlee, avec une meilleure absorption dans la gamme bleu-vert visible, accompagnée d'une conductivité électrique faible. L'amélioration de ces propriétés optiques est un signe prometteur pour une potentielle intégration photovoltaïque.
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Katkhouda, Kamal [Verfasser], Peter [Akademischer Betreuer] Schaaf, Edda [Akademischer Betreuer] Rädlein, and Andreas [Akademischer Betreuer] Grohe. "Aluminum-based PVD rear-side metallization for front-junction nPERT silicon solar cells / Kamal Katkhouda. Technische Universität Ilmenau. Gutachter: Edda Rädlein ; Andreas Grohe. Betreuer: Peter Schaaf." Ilmenau : Universitätsbibliothek Ilmenau, 2014. http://d-nb.info/1070505129/34.
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Vettori, Marco. "Growth optimization and characterization of regular arrays of GaAs/AIGaAs core/shell nanowires for tandem solar cells on silicon." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEC010/document.
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L'objectif de cette thèse est de réaliser l'intégration monolithique de nanofils (NFs) à base de l’alliage Al0.2Ga0.8As sur des substrats de Si par épitaxie par jets moléculaires via la méthode vapeur-liquide-solide (VLS) auto-assistée et de développer une cellule solaire tandem (TSC) à base de ces NFs.Pour atteindre cet objectif, nous avons tout d'abord étudié la croissance de NFs GaAs, étape clé pour le développement des NFs p-GaAs/p.i.n-Al0.2Ga 0.8As coeur/coquille, qui devraient constituer la cellule supérieure de la TSC. Nous avons montré, en particulier, l'influence de l'angle d'incidence du flux de Ga sur la cinétique de croissance des NFs GaAs. Un modèle théorique et des simulations numériques ont été réalisées pour expliquer ces résultats expérimentaux.Nous avons ensuite utilisé le savoir-faire acquis pour faire croître des NFs p-GaAs/p.i.n-Al0,2Ga0,8As coeur/coquille sur des substrats de Si prêts pour l'emploi. Les caractérisations EBIC réalisées sur ces NFs ont montré qu'ils sont des candidats potentiels pour la réalisation d’une cellule photovoltaïque. Nous avons ensuite fait croître ces NFs sur des substrats de Si patternés afin d'obtenir des réseaux réguliers de ces NFs. Nous avons développé un protocole, basé sur un pré-traitement thermique, qui permet d'obtenir des rendements élevés de NFs verticaux (80-90 %) sur une surface patternée de 0,9 x 0,9 mm2.Enfin, nous avons consacré une partie de notre travail à définir le procédé de fabrication optimal pour la TSC, en concentrant notre attention sur le développement de la jonction tunnel de la TSC, l'encapsulation des NFs et le contact électrique supérieur du réseau de NFsThe objective of this thesis is to achieve monolithical integration of Al0.2Ga0.8As-based nanowires (NWs) on Si substrates by molecular beam epitaxy via the self-assisted vapour-liquid-solid (VLS) method and develop a NWs-based tandem solar cell (TSC).In order to fulfil this purpose, we firstly focused our attention on the growth of GaAs NWs this being a key-step for the development of p-GaAs/p.i.n-Al0.2Ga0.8As core/shell NWs, which are expected to constitute the top cell of the TSC. We have shown, in particular, the influence of the incidence angle of the Ga flux on the GaAs NW growth kinetic. A theoretical model and numerical simulations were performed to explain these experimental results.Subsequently, we employed the skills acquired to grow p-GaAs/p.i.n-Al0.2Ga0.8As core/shell NWs on epi-ready Si substrates. EBIC characterizations performed on these NWs have shown that they are potential building blocks for a photovoltaic cell. We then committed to growing them on patterned Si substrates so as to obtain regular arrays of NWs. We have developed a protocol, based on a thermal pre-treatment, which allows obtaining high vertical yields of such NWs (80-90 %) on patterned Si substrates (on a surface of 0.9 x 0.9 mm2).Finally, we dedicated part of our work to define the optimal fabrication process for the TSC, focusing our attention to the development of the TSC tunnel junction, the NW encapsulation and the top contacting of the NWs
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Veinberg, vidal Elias. "Fabrication, caractérisation et simulation de cellules solaires multi-junction III-V sur silicium." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT091/document.
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Des rendements record à plus de 26% ont récemment été démontrés avec des cellules solaires en Si, approchant la limite théorique de 30% pour une seule jonction. Les cellules solaires à multi-jonctions (MJSC) fabriquées à base de matériaux III-V peuvent dépasser cette limite: des rendements supérieurs à 45% ont été reportés pour une cellule à 5 jonctions sous un soleil et pour une cellule à 4 jonctions sous lumière concentrée. Cependant, pour des applications terrestres, le coût élevé de ces technologies impose l’utilisation d’une haute concentration, ce qui augmente la complexité du système.Une solution intermédiaire consiste à fabriquer des cellules solaires III-V à haut rendement sur des substrats Si, moins coûteux que les substrats III-V ou Ge utilisés dans les MJSC classiques. Des rendements supérieurs à 33% ont déjà été démontrés pour des MJSC fabriquées par collage direct. Ceci, combiné aux progrès récents dans la réutilisation des substrats III-V, présage un avenir prometteur pour les cellules solaires tandem III-V sur Si, ce qui pourrait mener à la prochaine génération de systèmes photovoltaïques à haut rendement et faible coût.Dans ce travail de thèse, des cellules solaires tandem AlGaAs//Si à 2 jonctions (2J) et GaInP/AlGaAs//Si à 3 jonctions (3J) ont été fabriquées par collage direct, ce qui a donné lieu à une configuration à 2 terminaux (2T).Différentes techniques de collage ont été étudiées, notamment une approche innovante présentant un potentiel d'industrialisation prometteur pour l’intégration des matériaux III-V sur Si. Les propriétés électriques de l'interface de collage GaAs//Si ont été analysées à l'aide de dispositifs de test dédiés conçus au CEA, permettant d'évaluer la résistance d'interface et le mécanisme de conduction.Des caractérisations et simulations expérimentales ont été effectuées afin d'optimiser le design et le processus de fabrication, conduisant à des rendements record. Pour la sous-cellule supérieure en AlGaAs de la 2J, cela comprend l'utilisation d'une fenêtre en AlInP avec un émetteur en GaInP, formant une hétérojonction n-GaInP/p-AlGaAs, qui améliore les performances pour les faibles longueurs d'onde. De plus, la réduction de l'épaisseur de la couche de collage en GaAs et l'utilisation d'une jonction tunnel en AlGaAs, avec bande interdite plus large, augmentent la transparence et donc le photocourant de la sous-cellule inférieure.Pour la sous-cellule inférieure en Si, les simulations ont permis d'identifier les facteurs clés qui limitent les performances, la durée de vie étant la caractéristique la plus critique dans les cellules Si épaisses utilisées. Dans le cas des interfaces III-V//Si, un émetteur fortement dopé est essentiel pour minimiser la recombinaison de surface et donc augmenter la tension en circuit ouvert. La passivation de la surface arrière est également importante, notamment pour augmenter la réponse dans l’infrarouge. Différents processus de diffusion et d'implantation ont été étudiés pour former l'émetteur. Les processus d'implantation ont montré moins de dégradation de la durée de vie et des surfaces moins rugueux, permettant ainsi le collage sans planarisation chimico-mécanique et donc des niveaux de dopage plus élevés en surface.Finalement, afin d’évaluer correctement le rendement de conversion de ces cellules tandem III-V sur Si, une méthode de caractérisation courant-tension rapide et peu coûteuse, adaptée aux MJSC sous faible concentration a été développée. Cette méthode ne nécessite pas de cellules isotypes parfaitement identiques, à la place, des cellules Si à simple jonction avec filtres optiques sont utilisées. Une efficacité de 23,7% sous 10 soleils a été démontrée de cette manière pour la cellule AlGaAs//Si, qui est le rendement le plus élevé signalé à ce jour pour une cellule tandem à base de Si avec 2J et 2TSi solar cells with record efficiencies over 26% have been recently demonstrated, approaching the Si single-junction limit of 30%. Multi-junction solar cells (MJSC) based on III-V materials can overcome this limit: efficiencies over 45% have been reported for a 5-junction under 1 sun and for a 4-junction under a concentrated illumination of 300 suns. Due to their elevated cost, these cells could be used in terrestrial applications only if operated under very high sunlight concentration for commercial terrestrial applications, which in turn increases the module and system complexity.An intermediate solution consists in fabricating high efficiency III-V solar cells on Si substrates, which are less expensive than the III-V or Ge substrates used in conventional MJSC. Mechanical-stacked and wafer-bonded solar cells, which avoid the unresolved issues of III-V on Si epitaxy, have already demonstrated efficiencies over 33%. This, combined with the recent advancements in the field of substrate reuse, predict a promising future for III-V on Si tandem solar cells, which could lead the next generation of high-efficiency and low-cost photovoltaics.In this PhD work, 2-junction (2J) AlGaAs//Si and 3-junction (3J) GaInP/AlGaAs//Si tandem solar cells were fabricated. The Si bottom subcell and the III-V top subcell(s) were joined together by wafer bonding, resulting in a 2-terminal (2T) III-V//Si solar cell configuration.Different wafer bonding techniques were studied, including an innovative bonding approach showing promising industrialization potential and thus, opening a new path for III-V on Si processing. The GaAs//Si bonding interface electrical properties were analyzed using dedicated test devices originally conceived at CEA, allowing to evaluate the interface resistance and the conduction mechanism.Experimental characterizations and simulations were performed in order to optimize the design and fabrication process, leading to record efficiencies. For the AlGaAs top subcell of the 2J, this includes the use of an AlInP window together with a GaInP emitter, forming an n-GaInP/p-AlGaAs heterojunction, which improved the short wavelength performance. In addition, the reduction of the GaAs bonding layer thickness and the use of a higher bandgap AlGaAs tunnel junction resulted in a higher transparency and a bottom subcell photocurrent improvement.For the Si bottom subcell, simulations allowed to identify the key factors that limit the performance, being the bulk lifetime the most critical characteristic in the thick Si cells used. In the case of III-V//Si interfaces, a highly doped emitter is crucial to minimize the surface recombination and maximize the open-circuit voltage, outweighing the drop in short-circuit current due to lifetime degradation. Back surface passivation is also important, specially to increase the infrared response. Different diffusion and implantation processes for the emitter formation were studied. Implantation processes showed less bulk lifetime degradation and smoother surfaces, thereby allowing bonding without chemical-mechanical planarization and thus higher doping levels at the surface.Finally, in order to correctly assess the efficiency of these III-V on Si tandem cells, a fast and low-cost current-voltage characterization method adapted for MJSC under low concentration was developed. This method does not require perfectly matched component cells and instead, Si single-junction cells with optical filters are used as pseudo-isotypes. An efficiency of 23.7% under 10 suns was demonstrated this way for the AlGaAs//Si cell, which is the highest efficiency reported to date for a 2J 2T Si-based tandem cell
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Shafai, Adam, and Wei Zhao. "Kiselkarbidtransistorer i växelriktare för solceller." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177197.
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Since the first commercial silicon carbide (SiC) transistor was released, the interest in SiC has grown exponentially [1]. The wide energy band gap, high critical electric field and thermal conductivity of silicon carbide allow it to withstand higher voltage/current gains than conventional semiconductor materials [2]. The electrical properties of SiC enable integrated devices and circuits to operate at higher voltages and temperatures. One of the most attractive applications for SiC is in inverters for photovoltaic systems, where switching time is of great importance. This thesis presents the study of two bipolar junction transistors (BJT), FSICBH15A120 of SiC and BUV48A of conventional silicon (Si). The transistors were simulated and validated experimentally, then tested in a DC/AC pv inverter with a polycrystalline solar module of 36 solar cells as power source. The simulation results showed high efficiency and low power losses.Sedan den första kommersiella transistorn av kiselkarbid (SiC) släpptes har intresset för SiC ökat exponentiellt [1]. Det breda energibandgapet, höga kritisk elektriska fältstyrkan och termiska ledningsförmågan i SiC gör att den klarar en högre kombination av spänning/strömförstärkning än konventionella halvledarmaterial [2]. De elektriska egenskaperna av SiC gör det möjligt för integrerade komponenter och kretsar att arbeta i högre spänningar och temperaturer. Ett av de största användningsområdena för SiC är i växelriktare för solceller, där switch-tid har stor betydelse. I detta examensarbete presenteras studien av två bipolära transistorer (BJT), FSICBH15A120 av SiC och BUV48A av konventionellt kisel (Si). Transistorerna simulerades och valideras experimentellt, och slutligen jämfördes med varandra i en DC/AC-omvandlare med en polykristallin solpanel av 36 solceller som strömkälla. Hög verkningsgrad och låga energiförluster påvisades.
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Moulin, Nelly. "Cellules solaires à haute tension de fonctionnement à basede Silicium ultra mince nanostructuré." Thesis, Lyon, 2021. http://www.theses.fr/2021LYSEI002.
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Les technologies actuelles sont marquées par une augmentation exponentielle du nombre d’objets connectés. Ceux-ci sont intégrés dans tous les domaines et s’accompagnent d’un enjeu de taille : leur approvisionnement en énergie. Dans cette thèse, on propose une nouvelle architecture de cellule solaire en Silicium pouvant s’intégrer facilement dans le design d’un objet connecté. Cette cellule est constituée de plusieurs sous-cellules mises en série par des jonctions tunnels verticales. La jonction tunnel a été étudiée analytiquement par le développement de deux nouveaux modèles sur sa caractéristique I(V). Par la suite, un procédé de fabrication a été mis en place pour la réalisation de jonctions tunnels verticales auto-alignées. Un premier démonstrateur de cellule solaire a été réalisé et a produit 200 mV de tension de sortie pour une cellule de 18 µm de large. L’effet de cascade de sous-cellules a également pu être montré sur des cellules contenant jusqu’à 10 jonctions tunnels. Par ailleurs, des options d’améliorations ont été proposées ainsi que des études sur la diminution des sources de résistance dans la cellule. Cette thèse étudie les phénomènes physiques interagissant dans une cellule à jonctions tunnels verticales de manière analytique, par simulation optique, physique et électrique ainsi que de manière expérimentaleCurrent technologies see an exponential increase in the number of connected objects. These objects are integrated in every domain and come along with an important challenge: their energy supply. In this thesis, we propose a new Silicon solar cell architecture that is easy to integrate in a chip design. This solar cell is composed of several subcells connected in series by vertical tunnel junctions. We study the tunnel junction from an analytical point of view and develop two new models on the I(V) characteristic. Then, we develop a new process flow to fabricate auto-aligned vertical tunnel junctions. With this process flow, a first prototype shows 200 mV output voltage for an 18 µm wide cell. We could also demonstrate the impact of series connection on cells containing up to 10 tunnel junctions. Several optimisations solutions have been proposed and investigated, notably on the resistance sources. This thesis studies physical phenomena interacting in a vertical tunnel junction solar cell from an analytical point of view, with optical, physical and electrical simulations along with experiments
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Chen, Da-Shin, and 陳達欣. "Optimization of Hydrogenated Amorphous Silicon Single-Junction Solar Cells." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/76430473136478895068.
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碩士國立交通大學
顯示科技研究所
98
In this study, hydrogenated amorphous silicon (s-Si:H) solar cell was fabricated by plasma enhanced chemical vapor deposition (PECVD). First, we optimized condition of the deposited single layer for p-layer, i-layer and n-layer, respectively. In order to investigate film property, the optoelectronic and optical properties was measured by Fourier Transform Infrared Spectroscopy (FTIR), UV/VIS/NIR spectrometers. The property of hydrogenated amorphous silicon carbide (a-SiC:H) p-layer was measured and discussed. Comparing the photovoltaic performances of the as grown solar cell with p-layer for a-Si:H and a-SiC:H ,respectively. By using wide bandgap p-layer, the open-circuit voltage (Voc) increased from 0.75V to 0.78V with corresponding short-circuit current (Jsc) increased from 10.23mA/cm2 to 12.76mA/cm2. Post-treatment of the cell was also carried out and significant increase in the fill factor (FF), efficiency, and Voc were observed. The experiment result showed an improvement between the Ag back electrode and amorphous n-layer. Different cell area of 2×2 cm2 and 1×1 cm2 were also fabricated. A cell conversion efficiency of 8.67% was achieved for a cell area of 2×2cm2.
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Huang, Jiun-Sung, and 黃俊淞. "Numerical modeling of silicon-based single-junction and multi-junction solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/53030387453989508736.
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碩士國立東華大學
光電工程學系
99
As the quality of life improves, the demand of energy sources of human beings also increases. However, due to the massive consumption of current energy sources on the earth, many different types of renewable energy sources have been developed. Among all the renewable projects in progress, solar energy is the most promising as a future energy technology, because it is the most abundant energy source. In this thesis, we have investigated single junction amorphous solar cells, single junction microcrystalline solar cells, and multi-junction solar cells by the computer simulation tool, Sentaurus TCAD. For an accurate simulation of microcrystalline solar cells, the simulation model considered the grain boundary. In order to absorb wider spectrum of the sun, the concept of multi-junction solar cell was introduced. For reducing the production cost of the manufacturing process, a suitable current matching point is necessary. In the micromorph solar cell, the infrared absorption of microcrystalline silicon is not strong enough. Therefore, adding another lower-bandgap material will compensate the drawback. We used Ge material as the bottom sub-cell in the triple-junction solar cell. The band gap of Ge is 0.66 eV. Therefore, there is effective absorption of infrared in the triple-junction solar cell. In this study, the two junction cell achieved a Jsc of 11.69 mA/cm2, a Voc of 1.50 V, and an efficiency of 10.59 %. Meanwhile, the triple junction achieved a Jsc of 11.30 mA/cm2, a Voc of 1.69 V, and an efficiency of 12.7 %. The results clearly indicated that an additional Ge layer could enhance the Voc of tandem solar cells.
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Cheng, Po-Hsiang, and 鄭柏翔. "High Efficiency Single-Junction Hydrogenated Amorphous Silicon Thin-Film Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/05428604144234725853.
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碩士國立交通大學
光電工程學系
99
In the thesis, device quality hydrogenated amorphous silicon thin film was deposited by plasma enhanced chemical vapor deposition (PECVD) with hydrogen diluted silane. This high quality intrinsic hydrogenated amorphous silicon film was served as the absorber layer in solar cells. When depositing the devices, the electrode spacing and thicknesses of p-type, intrinsic amorphous silicon carbide, intrinsic layer, and n-type amorphous silicon were optimized to be incorporated into the solar cells. Methods of bandgap profiling in the buffer layer between p-layer and i-layer as well as hydrogen plasma treatment at each interface, were applied to optimize the solar cells. As a result, a record solar cell conversion efficiency was enhanced to 9.46%.
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Hung, Wei-Jie, and 洪偉傑. "Fabrication of Transparent Conductive Oxides for Single-Crystalline n-type Silicon Hetero-Junction Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/50732695248536570600.
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碩士華梵大學
機電工程學系博碩專班
98
This paper is aimed to improve the efficiencies of silicon solar cell using semiconductor fabrication technologies. The research first adopts n-type (100) silicon wafers as substrates, and applies KOH etching in the photolithography process to form inverted pyramid structures. The density of the inverse pyramid structures is varied to investigate its impact factor on the reflectivity for the solar cells. In addition, the paper performs high-density plasma chemical vapor deposition to fabricate amorphous silicon thin films. Then, the author can study solar cells performances with single crystal / hydrogenised amorphous silicon heterojunctions, the effects of p-type amorphous silicon films deposited over p-type single crystal films, as well as the influences from p-type amorphous silicon layers and intrinsic layers. Also, the research executes ion implantation to fabricate BSF layers, which are intended to decrease the carrier recombination rate within the interfacing regions, and to improve the minority carrier collection rates. Furthermore, this research employes RF sputtering system to fabricate AZO transparent conductive thin films, and then learns the effects of adjusted processing parameters to the electrical and optical film properties. In the end, hydrogen plasma is used to perform the film post-processing, and the conductive films are then utilized as solar cell electrodes. After using a semiconductor parameter analyzer to perform a series of experimental measurements, the obtained IV curves suggest that the prototyped solar cells can obtain an open circuit voltage Voc = 0.60V, a short circuit current Jsc = 30mA/cm2, a fill factor FF of 62.08%, and an actual efficiency is about 11.13%.
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Hsiao, Min-Wen, and 蕭閔文. "Improvement of Microcrystalline Silicon Single-Junction and Tandem Solar Cells by Optimizing N-Type Microcrystalline Silicon and Silicon Oxide as Doped and Back Reflecting Layers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/krs8f5.
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Tu, Wen-Hsiang, and 涂文翔. "Development and Application of Wide-Bandgap Hydrogenated Amorphous Silicon Suboxide in Amorphous Silicon-Based Single-Junction and Tandem Solar Cell." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/3n9pjm.
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碩士國立交通大學
光電工程研究所
103
The wide-bandgap hydrogenated amorphous silicon suboxide (a-SiOx:H) for amorphous silicon-based solar cell application has been investigated. The silicon-based solar cells was deposited by plasma-enhanced chemical vapor deposition (PECVD) technique. First of all, the undoped a-SiOx:H layer was studied. By adding CO2 as the source gas, the oxygen atoms can be incorporated into the film. The oxygen incorporation widened the bandgap so that wide-bandgap material was obtained, but reduced the photo conductivity which can be referred to the increase in defects in the film. We further adjusted the substrate temperature and hydrogen dilution for high-quality a-SiOx:H absorber. Application of the optimized a-SiOx:H absorber obtained the cell efficiency of 4.92% with the VOC of 910 mV, the JSC 8.55 mA/cm2 and the FF of 63.25%. Besides, employment of a-SiOx:H(n) in a-SiOx:H single-junction solar cell enhanced the JSC to 9.60 mA/cm2. As compared to the a-Si:H cell with a-SiOx:H(p) deposited at H2-to-SiH4 flow ratio of 2.7, the a-Si:H cell with a-SiOx:H(p) deposited at H2-to-SiH4 flow ratio of 150 had higher efficiency. In addition, the double p-layers were needed to reduced interface defect. Employment of 6-nm-thick a-SiOx:H(p)/ 8-nm-thick a-SiCx:H(p) as window layer in a-Si:H single-junction solar cell enhanced the cell efficiency to 7.37% with the JSC of 13.73 mA/cm2, the FF of 60.24 and VOC of 0.89 V. Finally, in a-Si:H/a-Si1-xGex:H tandem cell employment of the 6-nm-thick a-SiOx:H(p)/ 8-nm-thick a-SiCx:H(p) and a-SiOx:H(n) as window layer and n-layer of top cell enhanced the cell efficiency from 8.19 to 8.90% by increasing the JSC from 8.21 to 8.38, the FF from 64.37 to 67.68 and the VOC from 1.55 to 1.57 eV. Besides, the total JEQE was increased from 18.34 to 18.63 mA/cm2, which revealed that employment of wide-bandgap a-SiOx:H(p) and a-SiOx:H(n) in top cell reduced absorption loss in doped layer.
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BAI, WEN-BIN, and 白文賓. "Performance enhancement of single-junction GaAs solar cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8544hv.
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碩士國立臺北科技大學
光電工程系
106
In this study, the conversion efficiency of single-junction GaAs solar cells using (a) double layer (ITO/SiO2) anti-reflection and (b) metal/oxide/semiconductor (MOS) structure deposited by thermally RF-sputter were proposed and demonstrated. Optical reflectance, external quantum efficiency, dark current-voltage, and photovoltaic current-voltage of are measured and compared. Type-(a): The optical reflectance of double layer anti-reflection was simulated using TFCalcTM optical thin film software to show a low reflective spectrum at the GaAs solar cells. That in the GaAs solar cells with ITO (41 nm) and SiO2 (58 nm) double-layer anti-reflection layer exhibited the best short circuit current density enhancement, its short circuit current density enhancement (ΔJsc) of 28.43% (from 22.19 mA/cm2 to 28.50 mA/cm2) and conversion efficiency enhancement (Δη) of 30.35% (from 18.78% to 24.48%) were obtained. Type-(b): GaAs solar cells are fabricated using metal-oxide/semiconductor (MOS) structures using Al2O3 or TiO2 as a oxide films, Applying various voltages on the ITO electrode to enhance photovoltaic performance was observed, For the a case of MOS-structure cell, Al2O3/ITO, the short-circuit current density enhancement (ΔJsc) of 15.25% (from 22.69 mA/cm2 to 26.15 mA/cm2) and conversion efficiency enhancement (Δη) of 13.35% (from 18.28% to 20.72%) were obtained; and the oxide layer was TiO2 sputtered ITO transparent electrode (TiO2/ITO), the short-circuit current density enhancement (ΔJsc) of 21.09%(from 23.14 mA/cm2 to 28.02 mA/cm2) and conversion efficiency enhancement (Δη) of 22.40% (from 18.75% to 22.95%) were obtained. To study the biase effection MOS GaAs solar cell, the cell biased at -3.6 V, Jsc of 34.43 mA/cm2, and η of 26.50% foe the cell with Al2O3/ITO were obtained. Similarly, the cell with TiO2/ITO and biased at -3.6 V, Jsc of 36.64 mA/cm2 and η of 28.07% were obtained.
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Wang, Jia-Jiun, and 王家濬. "Manufacturing and Analysis of Hetero-Junction Solar Cells and Single-Crystalline Solar Cells." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/71620896146909935590.
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碩士華梵大學
機電工程學系博碩專班
96
Solar cells have the potential to be an important contributor to the global energy demand by the 21-st-century.The dominant topics for solar cell covered in this dissertation are (1) variation in the emitter dopant’s concentration,(2)variation in the wafer dopant’s concentration, (3)variation in the contact resistance,(4)the bifacial light source effects solar cells, (5)design and analysis micro Fresnel lens thin film. This work established a baseline model for silicon based solar cells and from this model the device physics relating to dopant’s concentration, contact resistance, bifacial light source was studied. The micro-Fresnel lens thin film was composed of Fresnel lens, the micro-Fresnel lens thin film has the capability to increase the light utility.
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Chiu, Ming-Hui, and 邱銘暉. "Deeply Etched Single Crystalline Silicon Solar Cells." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/84687497281207943571.
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Chen, Yen Jia, and 陳彥家. "Fabrication of Graphene on Silicon nanowires Schottky Junction Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/7zq5pk.
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碩士國立清華大學
材料科學工程學系
105
Graphene, as a two-dimensional carbon material with only one carbon atom thickness, has shown many superior material properties, including high optical transmittance, excellent mechanical flexibility, low resistivity, and high carrier mobility. Theoretically, a Schottky junction can be formed by transferring graphene onto the surface of a moderately doped semiconductor. Thus, graphene is expected to have great potential in the field of photovoltaics. This study aims to fabricate the graphene/silicon nanowires Schottky junction solar cells, with the expectation to enhance the solar cell’s efficiency by combining the excellent antireflection property of silicon nanowires and the advantages of graphene mentioned above. We started at controlling the length of silicon nanowires by changing the etching time, and founded that the silicon nanowires’ length becomes longer with the etching time increased. After fabrication into solar cells, the device made from etching time of 20 minutes showed a maximum efficiency of 1.566%. And then the H2O2 was added into the etching solution to get silicon nanowires of different structures. The results showed that when the etching time was 8 minutes, the solar cell showed a maximum efficiency of 0.937%. In the end of the study, we compared the solar cells fabricated by both etching methods. In general, the devices made from the H2O2-free etching solution exhibited better efficiencies.
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Hsieh, W. C., and 謝文章. "Fabrications and Characteristics of Ⅲ-ⅤCompounds Multi-Junction Solar Cells and PIN Silicon Thin Films Solar Cells." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/53730773229023469313.
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碩士南台科技大學
電子工程系
97
In this study, we found that the efficiency of the well-fabricated multi-junction solar cells was only 0.982%. By using the IPCE measurement, we found that the solar cells almost did not react with visible light. We supposed that GaAs contact layer absorbed the visible light, so that the devices did not react with visible light. For verifying this supposing, we etched the GaAs contact, and the efficiency could be improved from 0.982% to 2.63%. But the devices did not react with visible light on IPCE measurement. So we supposed the InGaP cell caused the issue. For making sure the supposing, we etched the InGaP epitaxial layers by wet etching, and measured the transforming efficiency. The efficiency of the single junction GaAs solar cells was 9.31%. And the devices did react with visible light on IPCE measurement. So InGaP epitaxial layers caused the bad efficiency. On the Si thin film solar cells, we first grew the p-type Si thin film by changing fabrication power and fabrication pressure, and analyzed the thin films with same thickness but different fabrication conditions. We found that the thin films had better resistivity and carrier concentration at high power and low pressure. So we merged the two conditions to fabricate the best p-type Si thin films. And we used the same method to fabricate intrinsic Si and n-type Si thin films. The intrinsic and n-type thin films grown by high power and low pressure fabricating had better resistivity and carrier concentration as well. Finally, we used p-type, intrinsic, n-type layers to fabricate PIN solar cells. For efficiency measurement, the devices showed almost zero efficiency. This problem may caused by the amorphous Si thin films with many defects. So the devices did not have transforming efficiency.
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Shih, Zun-Hao, and 施圳豪. "The study of single and dual junction III-V solar cells." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/u43a33.
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碩士中原大學
電子工程研究所
93
The object of this study is to fabricate a series interconnected GaAs and InGaP solar cells respectively and particularly focuses on optimizing the most important part of these solar cells, base layer. For semiconductor devices, the carrier concentration influences the electrical properties of the materials. Both the short-circuit current and open-circuit voltage of the solar cell decreases with increasing carrier concentration. In addition, the layer thickness is another essential issue of the output electrical characteristics of device. A thicker layer will absorb more quantity of incident light, but too thick a layer causes an increase in both series resistance and dark current, which will degenerate the performance of the device. We found the optimum values for the thickness and concentration of the device’s active layer through this study. The DJ solar cell is made up of GaAs and InGaP SJ solar cell in series connection. The current mismatching between InGaP and GaAs subcells limits the total photocurrent of the device. We took the results of the SJ solar cell experiments as the references for the DJ solar cell design and the main experiment variable was the base layer thickness of InGaP subcell. By varying base layer thickness and using laser light-bias I-V measurement, one could find the current limited cell clearly and the optimal design of the device. The current-voltage (I-V), external quantum efficiency (EQE) and thermal stability characteristics of the fabricated solar cells were measured by ISO-standard Simulator and homemade spectral response measurement system, respectively, at room and various temperatures.
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Yang, Chun-Chieh, and 楊竣傑. "Investigation of built-in electric field in single-junction solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/47399584457273780620.
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碩士中原大學
物理研究所
99
This thesis studied the built-in electric field of InGaP solar cells by electroreflectance(ER) measurements. With the increased bias, a decrease of the built-in electric field was found. Using current-voltage characteristics and the built-in electric field as a function of bias, we can get the information about the interface recombination velocity and minority carrier mobility. With the increased illumination power of a laser, a trend of decreasing built-in electric field was found. We fitted built-in electric field as a function of the illumiaiton power by a formula associated with the short-circuit current. Two kinds of GaAs solar cells under different illuminaiton power were measured by ER. The results show that built-in electric field in each GaAs solar cell has been reduced by increasing the illumination power. The decrease of the built-in electric field for these two solar cells was found to be different. Using a formula to fit the experiments, we found that the difference in the decrease of built-in electric fields is due to a difference of reverse saturation current.
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Chen, Guan-Lin, and 陳冠霖. "Optoelectronic Properties of i-Layer Thickness Dependence Single Junction Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/30452104507069109923.
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碩士中原大學
電子工程研究所
100
In this thesis, we reported the optoelectronic characteristics of p-i-n GaAs solar cells. We studied the optimum thickness of intrinsic layer for obtaining the highest conversion efficiency. The samples without were detected by current-voltage measurement under AM1.5G illumination that the sample with 1 nm intrinsic layer has the highest efficiency of 14.24％. Based on low temperature photoluminescence and time resolved photoluminescence measurement, localization depth in such intrinsic layer thickness was developed. The experimental result showed that both localization depth (Eloc) at 9.8 meV and radiative lifetime (τrad) at 5.3 ns were achieved the best optoelectronic performance in 1 nm intrinsic layer. It was found out that the localization formed due to Zn diffusion in n-GaAs and intrinsic layer. Different samples annealed at 650℃ with different annealing time were attained to obtain the localization depth. It was clearly revealed that the longer annealed time, leads to the deeper localization, and to the shorter life time. The ECV measurements manifest that the Zn concentrations are changed dramatically. The evidence shows clearly that the Zn presented nominally in the lower n-GaAs and i-GaAs layer, as the result of diffusion. Furthermore, it was proposed to distinguish the front surface recombination velocity from the induced defects by variation the PL intensity. From this photoluminescence measurement, the surface recombination velocity of the solar cells with the intrinsic layer 1 nm is obviously improved. As these results, the thickness of intrinsic layer indeed deeply influences the efficiency of solar cell.
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Lin, Yu-Keng, and 林宥庚. "Fabrication of Graphene and Silicon Textured Substrate for Schottky Junction Solar Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2vvvcc.
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碩士國立臺灣大學
材料科學與工程學研究所
106
The system consisting of graphene and textured silicon substrate with enhanced light harvesting was studied in the present work. The thesis is divided into two topics. In the first topic, Schottky junction solar cells based on n-type silicon nanowire arrays (SiNWs) and multi-layered graphene with 1–4 layers were assembled. The textured substrates enhanced the light-harvesting compared to planar substrates. Multi-layered graphene films produced by chemical vapor deposition and layer-by-layer stacking mitigated damages and increased the work function of graphene. Thus, both the power conversion efficiency and fill factor of Schottky junction solar cells could be increased with multi-layered graphene. It was found in the present study that the optimum photovoltaics performance of solar cells was achieved when double-layered graphene was used. The performance degraded with the number of graphene layers when it was more than 2 layers. While damages could be mitigated and the work function could be improved using multi-layered graphene in SiNWs Scottky junction solar cells, the optical transmittance of graphene would be reduced with excessive number of graphene layers. In the second topic, a simple and low-cost method using the combination of metal-assisted chemical etching (MacEtch) and anisotropic wet etching was performed to fabricate an anti-reflection inverted pyramidal cavities on dendrite-like textured silicon substrate. To achieve this, a thin Ag film was deposited on a n-type (100) silicon substrate to form agglomerated Ag particles and MacEtch was performed to obtain vertically aligned etching holes on Si substrate. Subsequently, anisotropic wet etching was conducted and the etchant would penetrate the porous structure to form inverted pyramidal cavities on dendrite-like structure. Using this two-step etching, excellent anti-reflection behavior was obtained for our textured substrates and the reflectance was reduced to 1.13% in the present work.
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Hung, Mu-Min, and 洪牧民. "Photovoltaic Characteristics of Single-Junction GaAs Solar Cells with Selective Filter Design." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/85914213125248536957.
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碩士國立交通大學
光電工程研究所
103
In detailed balance model, the efficiency of single-junction solar cells can be potentially as high as 33.5% under AM 1.5G illumination. However the best state-of-the-art devices are still far lower than those figures, even the electronic quality is nearly perfect. Therefore the efficiency gap should stem from the light management inside solar cells. Recently, Alta device, Inc. has successfully fabricated a thin-film GaAs single junction solar cell with conversion efficiency of 28.8%, under 1 sun illumination, which aggregates the loss of backward emission into substrate[1]. This factor can be highly relevant to the cell’s performance, especially open-circuit voltage (Voc), and maximizing Voc is generally considered as the last mile to approach ultra-high efficiency limit. In this work, we try to quantify the Voc enhancement in GaAs solar cells by reducing emission loss. The simulation tools are RCWA simulation and photon recycling model NREL developed recently. The top structures we simulate here are different cutoff wavelength thin film selective filter of alternate TiO2 and SiO2. After our calculation, the cutoff wavelength of 840 nm can make the biggest Voc enhancement 36.4meV compared with bare one, and the structure also has excellent anti-reflection ability for maintaining high Jsc. Our results also show that using this way to enhance Voc is especially suitable for cells with ordinary material quality. Therefore, the requests of ideal top structures for solar cells’ use are not only near-perfect anti-reflection, but the ability to minimize the emission loss.
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Lu, Wei-Yi, and 呂威毅. "Raman Scattering of i-Layer Thickness Dependence GaAs Single Junction Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/04836958785003244172.
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碩士中原大學
電子工程研究所
100
In this thesis we studied the Raman scattering of p-i-n gallium arsenide (GaAs) solar cells with different thicknesses of intrinsic layer. In Raman scattering, used a spatial correlation (SC) model we can explained the correlation length (L) and asymmetry of the longitudinal-optic phonon Raman spectrum. We found the sample with 1 nm thickness of intrinsic layer had the highest correlation length and symmetry. And from current-voltage measurement under AM1.5G illumination that find the highest conversion efficiency (η) in the same sample. Different annealing times 0, 5, 10, 20, 30 and 60 seconds are held at 650 oC in the intrinsic layer 1 nm. symmetric ratio and correlation length are decreased when annealing time is kept from0 to 60 sec. To verify Zn diffusion into the i-layer and base region. We used electrochemical capacitance voltage (ECV) measurement that observe the carrier concentration increased at intrinsic layer and the base region for 60 sec when annealed the 1 nm i-layer GaAs solar cell. The details of the experimental results and the application feasibility of Raman scattering of p-i-n gallium arsenide (GaAs) solar cells with different thicknesses of intrinsic layer in this thesis.
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Tsai, Jyun-Jhe, and 蔡俊哲. "Characterization of Crystalline Silicon-Based P-N Junction Solar Cells and Fabrication of Germanium MIS Thin Film Solar Cells." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/88929109377814583132.
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碩士國立臺灣大學
電子工程學研究所
96
In this these, some analyses of the commercial crystalline silicon-based P-N junction solar cells are reported. The ideality factor of the solar cell is found to be much larger than 1 and close to 2. It indicates the purity and quality of silicon wafers used for the solar cells are worse than the wafers used in IC industry. For the temperature effect of solar cells, both theoretical derivation and experiment results have been carried out. It is found that open-circuit voltage reduction is the dominant factor that leading to efficiency degradation at higher temperature. And the silicon substrate of the single crystalline solar cell, is found in (100) orientation by X-ray diffraction.Besides, strain technique is used on these commercial cells, including uniaxial and biaxial strain. The results show the fill factor is enhanced by the strain technique, and the efficiency improves due to the larger fill factor. The small-piece cells with biaxial strain are found with better improvement.About the thin film solar cells. Germanium is taken as the active layer due to the higher mobility and larger absorption coefficient as compared to silicon. A low temperature wafer bonding technique is introduced. This technique is taken to transfer a 1.3μm thin film crystalline germanium on a glass with indium tin oxide coated. Then, the thin film solar cells are fabricated with this substrate.
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Tsai, Jyun-Jhe. "Characterization of Crystalline Silicon-Based P-N Junction Solar Cells and Fabrication of Germanium MIS Thin Film Solar Cells." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2907200802075900.
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