Дисертації з теми "GaAs solar cells"
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Vandamme, Nicolas. "Nanostructured ultrathin GaAs solar cells." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112111/document.
Повний текст джерелаThe thickness reduction of solar cells is motivated by the reduction of production costs and the enhancement of conversion efficiencies. However, for thicknesses below a few hundreds of nanometers, new light trapping strategies are required. We propose to introduce nanophotonics and plasmonics concepts to absorb light on a wide spectral range in ultrathin GaAs layers. We conceive and fabricate multi-resonant structures made of arrays of metal nanostructures. First, we design a super-absorber made of a 25 nm-thick GaAs slab transferred on a back metallic mirror with a top metal nanogrid that can serve as an alternative front electrode. We analyze numerically the resonance mechanisms that result in an average light absorption of 80% over the 450nm-850nm spectral range. The results are validated by the fabrication and characterization of these multi-resonant super-absorbers made of ultrathin GaAs. Second, we use a similar strategy for GaAs solar cells with thicknesses 10 times thinner than record single-junction photovoltaic devices. A silver nanostructured back mirror is used to enhance the absorption efficiency by the excitation of various resonant modes (Fabry-Perot, guided modes,…). It is combined with localized ohmic contacts in order to enhance the absorption efficiency and to optimize the collection of photogenerated carriers. According to numerical calculations, the short-circuit current densities (Jsc) can reach 22.4 mA/cm2 and 26.0 mA/cm2 for absorber thicknesses of t=120 nm and t=220 nm, respectively. We have developed a fabrication process based on nano-imprint lithography and on the transfer of the active layers. Measurements exhibit record short-circuit currents up to 17.5 mA/cm2 (t=120 nm) and 22.8 mA/cm2 (t=220 nm). These results pave the way toward conversion efficiencies above 20% with single junction solar cells made of absorbers thinner than 200 nm
Tutu, F. K. K. "InAs/GaAs quantum dot solar cells." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1430283/.
Повний текст джерелаChen, Hung-Ling. "Ultrathin and nanowire-based GaAs solar cells." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS355/document.
Повний текст джерелаConfining sunlight in a reduced volume of photovoltaic absorber offers new directions for high-efficiency solar cells. This can be achieved using nanophotonic structures for light trapping, or semiconductor nanowires. First, we have designed and fabricated ultrathin (205 nm) GaAs solar cells. Multi-resonant light trapping is achieved with a nanostructured TiO2/Ag back mirror fabricated using nanoimprint lithography, resulting in a high short-circuit current of 24.6 mA/cm². We obtain the record 1 sun efficiency of 19.9%. A detailed loss analysis is carried out and we provide a realistic pathway toward 25% efficiency using only 200 nm-thick GaAs absorber. Second, we investigate the properties of GaAs nanowires grown on Si substrates and we explore their potential as active absorber. High doping is desired in core-shell nanowire solar cells, but the characterization of single nanowires remains challenging. We show that cathodoluminescence (CL) mapping can be used to determine both n-type and p-type doping levels of GaAs with nanometer scale resolution. n-type III-V semiconductor shows characteristic blueshift emission due to the conduction band filling, while p-type semiconductor exhibits redshift emission due to the dominant bandgap narrowing. The generalized Planck’s law is used to fit the whole spectra and allows for quantitative doping assessment. We also use CL polarimetry to determine selectively the properties of wurtzite and zincblende phases of single nanowires. Finally, we demonstrate successful GaAs nanowire solar cells. These works open new perspectives for next-generation photovoltaics
Feteha, Mohamed Yousef Mohamed. "Heterojunction AlGaAs-GaAs solar cells for space applications." Thesis, University of Central Lancashire, 1995. http://clok.uclan.ac.uk/18836/.
Повний текст джерелаRobertson, Kyle. "Optoelectronic Device Modeling of GaAs Nanowire Solar Cells." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39710.
Повний текст джерелаSCACCABAROZZI, ANDREA. "GaAs/AlGaAs quantum dot intermediate band solar cells." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/40117.
Повний текст джерелаKHALILI, ARASTOO. "Numerical study of InAs/GaAs quantum dot solar cells." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2712032.
Повний текст джерелаHardingham, Christopher Mark. "GaAs and GaAs/Ge solar cells : a device and materials study using SEM-EBIC." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267028.
Повний текст джерелаJames, Asirvatham Juanita Saroj. "Characterization of type-II GaSb quantum rings in GaAs solar cells." Thesis, Lancaster University, 2015. http://eprints.lancs.ac.uk/80244/.
Повний текст джерелаPelati, Daniel. "Elaboration of GaAs solar cells based on textured substrates on glass." Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS456.pdf.
Повний текст джерелаThe increasing demand for clean energy has driven research toward higher efficiency and lower cost solar cells. Gallium arsenide solar cells detain the record efficiency for single junction devices but the high cost of the substrate limits their applications. In this work, we investigate an alternative GaAs substrate based on a low cost silica support coated by a thin (20 nm) Germanium layer. This layer is nearly lattice-matched to GaAs and can be crystallized with a high (111) texture using Metal Induced Crystallization (MIC). However, this requires a careful optimization of the deposition and annealing parameters. Here, we use a specially designed in situ optical microscope to optimize the annealing sequence. In particular, we identified two crystallization pathways, of which one should be minimized to obtain a good (111) crystalline texture. We then perform the heteroepitaxy of GaAs on this Ge seed layer using Molecular Beam Epitaxy, keeping the initial (111) crystal texture. We identify specific growth conditions for the twin- and defect-free growth of GaAs on Ge(111) surfaces. We also observe the growth of GaAs adopting the (111)A polarity on Ge (111) rather than the expected (111)B orientation. Finally, we fabricate (111)-oriented GaAs solar cells with 15,9% efficiency on a monocrystalline GaAs(111)B substrate. The transfer to standard Ge(111) monocrystalline wafers and to our Ge-coated silica pseudo-substrates reveals doping issues related to the (111)A orientation of the GaAs, as well as surface roughening due to grain boundaries in the initial Ge seed layer
Boucher, Jason. "Studies of GaAs Solar Cells Grown by Close-Spaced Vapor Transport." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22284.
Повний текст джерелаRoyall, B. "GaInNAs/GaAs multiple quantum well and n-i-p-i solar cells." Thesis, University of Essex, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549286.
Повний текст джерелаDeng, Zhuo, and 鄧卓. "Luminescence and transport processes of charge carriers in the GaxIn₁-xP/GaAs double-junction tandem solar cells." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/211134.
Повний текст джерелаpublished_or_final_version
Physics
Doctoral
Doctor of Philosophy
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.
Повний текст джерелаColin, Clément. "Metallic nano-structures for light-trapping in ultra-thin GaAs and CIGS solar cells." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00998396.
Повний текст джерелаSINGULANI, ANDERSON PIRES. "SIMULATION AND DESIGN OF GAAS/ALGAAS QUANTUM WELL SOLAR CELLS AIDED BY GENETIC ALGORITHM." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15317@1.
Повний текст джерелаA energia é assunto estratégico para a grande maioria dos países e indústrias no mundo. O consumo atual energético é de 138,32 TWh por ano e é previsto um aumento de 44% até o ano de 2030 o que demonstra um mercado em expansão. Porém, a sociedade atual exige soluções energéticas que causem o menor impacto ambiental possível, colocando em dúvida o uso das fontes de energia utilizadas atualmente. O uso da energia solar é uma alternativa para auxiliar no atendimento da futura demanda de energia. O seu principal entrave é o custo de produção de energia ser superior as fontes de energia atuais, principalmente o petróleo. Contudo nos últimos 10 anos foi verificado um crescimento exponencial na quantidade de módulos fotovoltaicos instalados em todo mundo. Nesse trabalho é realizado um estudo sobre célula solares com poços quânticos. O uso de poços quânticos já foi apontado como ferramenta para aumentar a eficiência de células fotovoltaicas. O objetivo é descrever uma metodologia baseada em algoritmos genéticos para projeto e análise desse tipo de dispositivo e estabelecer diretivas para se construir uma célula otimizada utilizando esta tecnologia. Os resultados obtidos estão de acordo com dados experimentais, demonstram a capacidade dos poços quânticos em aumentar a eficiência de uma célula e fornecem uma ferramenta tecnológica que espera-se contribuir para o desenvolvimento do país no setor energético.
The energy is a strategical issue for the great majority of the countries and industries in the world. The current world energy consumption is of 138,32 TWh per year and is foreseen an increase of 44% until the year of 2030 which demonstrates a market in expansion. However, the society demands energy solutions that cause as least ambient impact as possible, putting in doubt the use of the current technologies of power plants. The utilization of solar energy is an alternative to assist in the attendance of the future demand of energy. Its main impediment is the superior cost of energy production in comparison with the current power plants, mainly the oil based ones. However in last the 10 years an exponential growth in the amount of installed photovoltaics modules worldwide was verified. In this work a study on solar cell with quantum wells is carried through. The use of quantum wells already was pointed as tool to increase the efficiency of photovoltaics cells. The objective is to describe a methodology based on genetic algorithms for project and analysis of this type of device and to establish directive to construct an optimized cell using this technology. The results are in accordance with experimental data, that demonstrates the capacity of the quantum wells in increasing the efficiency of a cell and supply a technological tool that expects to contribute for the development of the country in the energy sector.
Ibaceta, Jaña Josefa Fernanda. "Thermal instabilities of charge carrier transport in solar cells based on GaAs PN Junctions." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/145405.
Повний текст джерелаDentro de los factores que afectan negativamente una celda solar fotovoltaica se destaca la temperatura. Ya sea por imperfecciones del material o a condiciones de operación no uniformes, es posible que se concentre calor en una zona debido a la disminución de la resistencia local y su consecuente aumento de corriente eléctrica. Estas zonas de concentración de calor pueden estabilizarse, generando gradualmente degradación de la celda, disminución de su vida útil y eficiencia. En caso contrario, puede ocurrir un fenómeno de descontrol térmico que resulta catastrófico para la celda, inhabilitando su correcto funcionamiento. Estudios en módulos de película delgada revelan que esta condición ocurre incluso cuando la radiación está uniformemente distribuida y con ello, el perfil de temperatura inicial es constante. La evolución temporal, bajo radiación, induce zonas de calor que incrementan exponencialmente la temperatura, contrayendo su área; por otra parte, la temperatura de las zonas más alejadas disminuye simultáneamente mientras disipan pequeñas corrientes. Para evitar este fenómeno se pueden escalar propiedades del dispositivo, como aumentar la conductividad térmica y disminuir el espesor. Actualmente, estos análisis se realizan a partir de modelos numéricos y analíticos basados en el comportamiento de diodos y mediciones experimentales del perfil de temperatura en la capa superficial de la celda y en la juntura. El propósito de esta Tesis es determinar criterios de estabilidad electro-térmico que pueden ser utilizados para evitar el descontrol de temperatura a partir de aplicar un análisis a un modelo hidrodinámico de mayor complejidad que uno basado en diodos; más aún, considerar un estado fuera del equilibro entre la temperatura de la red y los portadores de carga. Se determinó que la inestabilidad ocurre en la juntura PN y depende fuertemente la temperatura de la juntura en los bordes. Además, aumentar la temperatura de los portadores, disminuir el largo y aumentar el voltaje aplicado pueden estabilizar el sistema, aumentando el tiempo en que el sistema duplica su temperatura.
Este trabajo ha sido parcialmente financiado por CONICYT-PCHA/Magíster Nacional/2016 - 22160729
Lépinau, Romaric de. "GaAs-on-Si solar cells based on nanowire arrays grown by molecular beam epitaxy." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS090.
Повний текст джерелаNanowires (NW) epitaxially grown on Si substrate are efficient light absorbers and allow to integrate high-quality III-V materials on Si by preventing defects induced by the lattice-mismatch between both materials. They provide a way to fabricate tandem III-V/Si solar cells above 30% efficiency. The goal of this thesis is to develop III-V NW solar cells grown on Si substrates. First, the control of the selective NW growth in ordered arrays on Si was addressed and vertical yields consistently above 90% and up to 100% were demonstrated. Using transmission electron microscope characterization, the growth conditions were optimized to improve the crystal quality by reducing the number of stacking faults, to investigate GaAsP NWs with the optimal bandgap for tandem, and to study core-shell heterostructures. Using cathodoluminescence to determine the carrier concentrations in NWs, it was shown that the core and the shell can be doped with Be up to p=8E18 cm⁻³, while Si is an amphoteric dopant, resulting in shell doping limited to n=5E17 cm⁻³. A solar cell fabrication process was developed to contact NW core-shell junctions. A first-generation GaAs homojunction device shows efficiencies up to 2.1%, limited by carrier collection issues, whereas the quasi-Fermi level splitting, estimated from PL measurements, reaches a promising value of 0.98 V at 82 sun, extrapolated to 0.86 V at 1 sun. A new core-shell p-i-GaAs/n-GaInP heterojunction exhibits efficiencies up to 3.7%, with a record Voc=0.65 V. These GaAs-based NW top-cells directly grown on Si pave the way toward high-efficiency tandem solar cells
Moushumy, Nazme A. "Silver (Ag) nanoparticle based masks for the development of antireflection subwavelength structures in GaAs and Si solar cells." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/862.
Повний текст джерелаJain, Nikhil. "Heterogeneous Integration of III-V Multijunction Solar Cells on Si Substrate: Cell Design and Modeling, Epitaxial Growth and Fabrication." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/52045.
Повний текст джерелаPh. D.
Barnes, Jennifer M. "An experimental and theoretical study of GaAs/InGaAs quantum well solar cells and carrier escape from quantum wells." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319305.
Повний текст джерелаPapež, Nikola. "Degradace solárních článků na bázi GaAs." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-438583.
Повний текст джерелаVettori, 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.
Повний текст джерелаThe 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
Baranov, Artem. "Cellules solaires à multijonctions par intégration monolithique de nitrures dilués sur substrats d’arséniure de gallium (GaAs) et de silicium (Si) : études des défauts." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS137/document.
Повний текст джерелаMulti-junction solar cells based on III-V compounds have reached very high power conversion efficiencies (46%). However, the fabrication methods that are generally used are complex and expensive for non-monolithic bonded and inverted solar cells. This thesis is devoted to the study of prospective methods to increase the efficiency of monolithic solar cells. The work is focused on the study of electronically active defects in the materials constituting the solar cells by means of photoelectric and capacitance techniques (admittance spectroscopy, DLTS,…) and it can be divided into three parts. The first part deals with single-junction solar cells wherein the absorber is made of i-layers of 1 eV bandgap InGaAsN compounds with various thicknesses grown as sub-monolayer digital alloys (SDA) of InAs/GaAsN by molecular-beam epitaxy (MBE) on GaAs wafers. The cell with 900 nm thick InGaAsN exhibits the best photovoltaic performance and no defects could be evidenced from capacitance techniques. When the thickness is increased to 1200 nm, defects were detected, but their concentration is low so it did not strongly affect the photoelectric properties. Further increase to 1600 nm of the layer thickness was shown to lead to a higher defect concentration causing a change in the band diagram of the structure and lowering the lifetime of photogenerated carriers. This could explain the drastic drop of the external quantum efficiency, and the overall poor performance of the solar cell. The second part is devoted to the study of single- and multi-junction solar cells with active layers of (In)GaP(As)N grown by molecular beam epitaxy (MBE) on GaP and Si wafers, respectively. More precisely, the active layers were either quaternary alloys of GaPAsN or SDAs of InP/GaPN. We found that p-i-n type solar cells with active layers of i-GaPAsN showed better performance than p-n type solar cells with active layers of n-GaPAsN due to higher EQE values. Moreover, solar cells with an i-GaPAsN absorber layer show better photoelectric properties and lower defect concentrations, than those with an SDA InP/GaPN absorber layer. Different defect levels were detected by capacitance methods in these materials and their parameters were described in detail. We showed that a suitable post-growth treatment could improve the electronic quality of the GaPAsN layer and the solar cell properties. Also, a triple-junction solar cell was fabricated with active layers of i-GaPAsN and i-GaPN. All subcells were found to be operating, leading to a large open circuit voltage (>2.2 V), but the overall performance is limited by the low value of the quantum efficiency due to low thicknesses of i-layers that should be increased for better absorption. Finally, the third part is devoted to the study of GaP layers grown on Si wafers at temperatures below 400 °C using an original method called plasma-enhanced atomic-layer deposition (PE-ALD). Indeed, it uses a plasma-enhanced chemical vapor deposition equipment and it is based on the alternate interaction of the wafer surface with Ga and P atoms coming from injected trimethylgallium and phosphine, respectively. We also grew layers using a continuous process (providing simultaneously the P and Ga atoms) and observed that their electric and structural properties were poorer than that grown by the proposed PE-ALD method. The influence of growth conditions on the GaP/Si heterostructures was explored. We found that low RF-plasma power leads to better photoelectric, structural and defect-related properties, due to a better passivation of the silicon wafer. In addition, we demonstrated that, contrary to results reported in the literature using MBE processes, our growth process does not affect the electronic properties of phosphorous doped n-Si wafers, while slight changes were observed in boron-doped p-Si wafers containing Fe-related defects, however without deactivation of the doping nor strong degradation of the electronic properties
Koroliov, Anton. "Semiconductor characterization by terahertz radiation pulses." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140922_141151-18493.
Повний текст джерелаŠio darbo tikslas buvo susipažinti su terahercinių impulsų generavimo ir detektavimo būdais, įsisavinti įvairias terahercinių impulsų panaudojimo metodikas bei pritaikyti jas puslaidininkių medžiagų ir puslaidininkinių prietaisų tyrimui. Buvo tirtos trys medžiagų grupės: GaAsBi, GaAs nanovielutės ir Cu – In chalkogenidai. Tyrimui buvo naudojamos: THz – TDS, optinio žadinimo – THz zondavimo, optinio žadinimo – optinio zondavimo bei THz sužadinimo spektroskopijos metodikos. Pagrindiniai rezultatai aprašyti disertacijoje yra šie: GaAsBi bandinių atkaitinimas stipriai sumažino krūvininkų gyvavimo trukmes, kas yra naudinga THz komponentų gamyboj. Optinio praskaidrėjimo efektas ir pikosekundžių eilės krūvininkų gyvavimo trukmės GaAsBi epitaksiniuose sluoksniuose su 10% ir daugiau Bi atomų stebimas žadinant juos optine spinduliuote, kurios bangos ilgiai siekia iki 1600 nm. Šios GaAsBi bandinių savybės leidžia juos priakyti įsisotinančių sugėriklių veidrodžių gamyboje. Bandiniai su GaAs nanovielutėmis emituoja THz spinduliuotę kelis kartus geriau nei GaAs padėklas, dėl padidėjusios sugerties, kurią skatina paviršinių optinių plazmonų rezonansai GaAs nanovielutėse. THz emisijos efektyvumas iš Cu-In chalkogenidų sluoksnių stipriai priklauso nuo jų stechiometrijos ir viršutinio skaidraus kontakto parametrų, ir gali būti naudojamas saulės elementų, pagamintų šių sluoksnių pagrindu, vidinių elektrinių laukų tyrimui.
Koroliov, Anton. "Puslaidininkių charakterizavimas terahercinės spinduliuotės impulsais." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140922_141205-51499.
Повний текст джерелаThe goal of this dissertation work was to develop pulsed terahertz radiation techniques and use them to study different properties of the semiconductor materials and semiconductor devices. Three groups of materials were investigated: GaAsBi, GaAs nanowires, copper-indium chalcogenide. The used techniques are THz-TDS, optical pump – THZ probe, optical pump – optical probe and THz excitation spectral measurements. The main results that were presented in this dissertation are the following: thermal annealing has resulted in the shortening of electron lifetime in GaAsBi to picosecond values, which is important achievement for the application of this material in THz range components. In GaAsBi layers with larger than 10% Bi content absorption bleaching recovering on the picosecond time scale and its saturation can be realized when the wavelengths of the optical signals are as long as 1600 nm. The results of these studies can be applied in the production of SESAM with bismide absorption layer. The samples with GaAs nanowires emit THz radiation several times better than the bulk GaAs substrates due to enhanced light absorption because of localized surface plasmon resonances in GaAs nanowires. THz emission efficiency from thin copper-indium chalcogenide layers strongly depends on their stoichiometry and on the parameters of the top transparent contact layers, thus it can be used for the mapping of built-in electric fields in solar cells made from these layers.
Koletsios, Evangelos. "GaAs/InAs multi quantum well solar cell." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/27856.
Повний текст джерелаAndre, Carrie L. "III-V semiconductors on SiGe substrates for multi-junction photovoltaics." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1100290985.
Повний текст джерелаYang, Cheng-Yu, and 楊正宇. "ZnSeO/GaAs Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/44077735985013342517.
Повний текст джерела國立中央大學
電機工程研究所
100
To date, materials with intermediate band become potential applications in solar cells because the spectral response could be extended by the intermediate band in the forbidden gap. In this thesis, we first demonstrated the ZnSeO based intermediate band solar cells and its characteristics were particularly investigated. The structural and optical properties of ZnSeO with varying oxygen content were studied in this work. The high absorption coefficients (>104 cm-1) of ZnSeO made it a promising candidate in solar cell. Theoretical calculation based on self-consistent drift-diffusion method was referred in this work. The results showed the conversion efficiency of ZnSeO based solar cell could reach 25 %. To realize the solar cell structure, ZnSeO with n-ZnO window layer were grown on p-GaAs substrate in this study. We also propose Ti/Al/Ni/Au ohmic contact to minimize the series resistance and power consume in solar cells, and low specific contact resistivity of 2.6×10-7 Ω-cm2 could be achieved. The ZnSeO based solar cells exhibit a 16 % increase of the short circuit current and same open circuit voltage in comparison to ZnSe based cells. Thus, a 43 % improvement in conversion efficiency could be obtained. However, existence of intermediate band could not be observed in ZnSeO solar cell because of the quality issues. This work does provide the opportunities for ZnSeO applied in photovoltaic devices.
Lin, Yan-Zhang, and 林彥璋. "Simulation of GaAs solar cells in nanoscale." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/47zcn2.
Повний текст джерела國立交通大學
光電系統研究所
106
We simulate both of optical and electrical modules into GaAs nanorod solar cell with SiO2 side-contact as the passivation of sidewall. In optical simulation, consider the height and thickness of SiO2 layer. Absorption, reflection and transmission were observed to know the influence of the SiO2 side-contact layer in the optical characteristic. Among this, also compute the total generation profile in nanorod which we assume as the interpolation of the generation rate into electrical simulation. In electrical simulation, study the height and thickness dependence of SiO2 contact layer. The all contact (top, side and bottom contact) are assumed as ideal contact which can ignore the relative resistance between metal and semiconductor connected. Under the set up above, SiO2 layer can enhance the current-voltage characteristic to higher Jsc. At short height of SiO2, the enhancement is probably unstable that Jsc moves up and down. while at tall height of SiO2 layer, the influence of passivation layer becomes lower that lead Jsc beginning decrease. In thickness dependence, the layer must be thick enough to obtain better performance efficiently. Since the nanorod solar cells have larger surface-to-volume ratio, surface recombination is an important factor which heavily influence the performance of nanoscale solar cells.
Huang, Pei-Hsuan, and 黃珮瑄. "Optimum design of GaAs triple-junction solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01872114017613334045.
Повний текст джерела元智大學
光電工程研究所
99
In this research, we study the efficiency enhancement in III-V compound semiconductor solar cell. In the first section of my thesis, we study the InGaP single junction solar cell with sub-wavelength surface texture structures by rigorous coupled wave analysis. The simulation of optimal structure result of the reflectance will be taken into APSYS software. The enhancement of the current density and efficiency were 2.39 % and 3.55 %, respectively. In the second section of my thesis, we present three processes to enhance the InGaP/GaAs/Ge triple junction solar cell efficiency. First, optimal the thickness of main absorption layer. The enhancement of the current density and efficiency were 9.29 % and 5.62 %, respectively. Second, optimum design of InGaP/GaAs/Ge triple-junction solar cells with sub-wavelength surface texture. The enhancement of the current density and efficiency were 6.90 % and 7.27 %, respectively. Third, combination optimal the thickness of main absorption layer with optimal sub-wavelength surface texture structure. The enhancement of the current density and efficiency were 16.27 % and 12.99 %, respectively.
Lee, Yueh-Mu, and 李岳穆. "Fabrication of GaAs Solar Cells on Silicon Substrates." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/73615424291525196364.
Повний текст джерела大葉大學
電機工程學系
95
Compared with silicon solar cell, single junction GaAs and multi-junction InGaP/GaAs solar cell grown on single-crystal GaAs substrates have achieved record efficiency of 25.7% and 29.5%, respectively, under AM1.5 illumination. 40% of efficiency has been achieved on InGaP/GaAs/Ge triple-junction solar cells. Even so, a signification cost reduction is needed for application of these solar cells to terrestrial photovoltaic systems. The cost for the manufacture of GaAs based solar cell can be attributed to the usage of single-crystal GaAs or Ge substrates and the utilization of epitaxy technology. In the thesis, a cheap material, silicon, was adopted as substrates. In order to use Si substrates for the growth of GaAs solar cells, an amorphous Ge film was deposited on Si substrate surface. Then, the amorphous Ge film was re-crystallized by a thermal annealing process. Finally, GaAs solar cell structure was grown on the poly-crystalline Ge film/Si substrates.
BAI, WEN-BIN, and 白文賓. "Performance enhancement of single-junction GaAs solar cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8544hv.
Повний текст джерела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.
Lin, Y. C., and 林裕鈞. "Process Study for the Fabrication of GaAs Solar Cells." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/13332939975570695625.
Повний текст джерела大葉大學
電機工程學系
96
Heavily doped n+-GaAs material plays important role in optoelectronics for the formation of ohmic contacts. Gold always is the popular metal for the electrode formation in the fabrication of optoelectronic devices. Regarding to solar cells, about 10% of cell area is covered with metal electrodes. In order to reduce the fabrication cost, cheaper metals shall be adopted for the formation of metal electrodes on solar cells. In this work, three kinds of metal combination, including Ni/Ag/Au, Ni/Al/Au, and Ni/Cu/Au, were deposited on n+-type GaAs to form non-alloyed ohmic contacts and be characterized, respectively. All samples were thermal treated with various different temperatures and times to evaluate the thermal stability. The characteristic contact resistances (ρc) were characterized by transmission line model (TLM). The inter-diffusions between metal and semiconductor after thermal treatment were characterized by X-ray diffractometer (XRD).
"High Efficiency GaAs-based Solar Cells Simulation and Fabrication." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.24949.
Повний текст джерелаDissertation/Thesis
M.S. Electrical Engineering 2014
Chen, Li Wei, and 陳勵瑋. "Fabrication of Inverted GaAs Solar Cells on Silicon Substrates." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99155898985047153281.
Повний текст джерела大葉大學
電機工程學系
98
This study is to investigate the fabrication of inverted GaAs solar cells on silicon substrates by wafer bonding and epitaxial lift-off technique. Conventional InGaP/GaAs/Ge-based triple junction solar cells with high conversion efficiency have been demonstrated. However, Ge junction contributes only 270 mV to open circuit voltage due to 0.66 eV of bandgap energy for Ge. By switching to InGaAs, the bandgap energy of this junction increases to 1.03 eV. Typical voltages of 550~650 mV can be generated, which enables it to be joined to InGaP/GaAs junctions without limiting the cell’s current. This approach involves growing InGaP and GaAs junctions that are lattice matched to a Ge or GaAs substrate in an inverted manner. Any dislocations are then confined to the InGaAs junction, which is deposited on top of the InGaP/GaAs dual junctions. Moreover, GaAs substrates removed by epitaxial lift-off technique are recyclable to save resource and prevent form waste. In this study, wafer bonding technique was applied to connect inverted GaAs solar cells and Si substrates by Au/Ag/Au and Au/Sn/Au. Then GaAs substrates were separated from inverted GaAs solar cells by epitaxial lift-off technique. Finally, the fabrication of inverted GaAs solar cells without any antireflection coating (ARC) was finished by photolithography. The measured open circuit voltage (Voc), short circuit current density (Jsc), fill factor (F.F.) and conversion efficiency (η) of the thin film GaAs solar cells on silicon substrates were 0.85V, 20.58mA/cm2, 0.74 and 12.8% respectively.
Cheng, Chieh-wen, and 鄭傑文. "Wafer-bonded PEDOT:PSS/GaAs thin-film hybrid solar cells and Wafer-scale PEDOT:PSS/Si hybrid solar cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/90953425913119300561.
Повний текст джерела國立交通大學
應用化學系碩博士班
104
In recent years, development of hybrid solar cells which combines the advantages from inorganic materials and organic solar cells provides a simple, low temperature process to fabricate solar cell devices with reduced cost. Content of this thesis work was divided into two parts. In the first part, we demonstrated a PEDOT:PSS on GaAs thin film hybrid solar cells by using wafer bonding and chemical wet etching techniques. The thin film hybrid solar cells reached an excellent power conversion efficiency efficiency of 8.93% when an additional p+ Al0.3Ga0.7As epi-layer is deposited on the surface of the solar cells to provide a front-surface field. However, we uncovered that the bonding materials was able to diffuse into the GaAs thin film during the wafer-bonding stage, which led to the decrease in efficiency. In the second part of the thesis, we demonstrated an 4 inch PEDOT:PSS/silicon hybrid solar cell device by adding the DuPont Capstone FS-31 surfactant into the spin-coated PEDOT:PSS layer. Effects of the non-uniformity of the PEDOT:PSS layer on cell performance was investigated. The device achieved an overall conversion efficiency of 10.25% and a total output current and voltage of 26.23 mA/cm2 and 0.46 V, respectively. The as-made large-area solar cells benefits from the reduction in the fabrication time and cost, and particularly in preventing the pollution from the wafer-cutting.
Wu, Po-Ching, and 吳柏慶. "Optical and electrical simulations of GaAs nanorod array solar cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/c84yxa.
Повний текст джерела國立交通大學
光電系統研究所
105
There have been many theoretical analyses and simulations about the anti-reflection and light-trapping properties of nanorod array solar cells, as well as the unique radial junction design. However, in continuity equations of electrical simulations, generation term of nanorod solar cells used to be approximated by Beer Lambert law same as the planar counterpart. In this work, we build the optical and electrical models of GaAs nanorod array solar cells by radio frequency and semiconductor module on COMSOL Multiphysics® software, and present the coupled optical and electrical results. In optical simulations, optimal nanorod array arrangement was obtained through light scattering and photocurrent analyses. In electrical simulations, doping and junction design were optimized through studies of current-voltage characteristics and electric field distributions. In addition, due to the high surface-to-volume ratio, surface defects and high surface states of III-V semiconductor interface would largely influence solar cells’ performances. We performed the numerical study on the influence of surface recombination velocity and interface barrier height. Finally, according to our simulation results, GaAs nanorod array solar cells can achieve 20% power conversion efficiency with good sidewall passivation.
Lee, Chyi-Lin, and 李奇霖. "Fabrication and Simulation Anaylsis of High Efficiency GaAs Solar Cells." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/13193936277442977376.
Повний текст джерела國立交通大學
電子物理學系
84
High efficiency solar cells can be applied on space satellites and power plants. GaAs solar cells is a good choice forhigh efficiency solar cell. In this research we will discuss thefabrication and theory simulation analysis of high- efficiency GaAssolar cells. In this research the method of image reversal is usedto produce the top contact of GaAs solar cells. Because of the image reversal technique, the width of fingers can be reduced from 400 ?m to 20 ?m. So the lateral resistance can be reduced and the fill factor will be improved. In this article we use the low-high junction model to analyze the GaAs solar cell. From the simulation how the structure parameter affect the solar cells preformance can be understood. So wecan use this result to design our solar cells. Moreover a spectral response system is established. From this system the quantum efficiency for all solar cell components can be investigated. We also successfully demonstrate a 15.6% GaAs solar cell.This efficiency is measured under AM1, one sun and without AR coating.We expect that if AR coating is used on the solar cell, the efficiency will increase by 2~3% and reach about 18%.
Tseng, Chun-Yen, and 曾俊硯. "Performance Improvement of GaAs Solar Cells Using Photoelectrochemical Oxidation Method." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/54392231118945623884.
Повний текст джерела國立成功大學
光電科學與工程研究所
97
The purpose of this research is to investigate the passivation mechanism of the window layer (AlGaAs) of GaAs solar cell by using photoelectrochemical oxidation method (PEC). The advantage of this passivation method is using its self-oxidation material to reduce the energy loss from the surface states on the window layer. The conversion efficiency of the GaAs solar cell with and without photoelectrochemical oxide treatment would be investigated. The conversion efficiency can be improved due to the reduction of surface state densities. Furthermore, in order to reduce the losses from the solar reflection, double anti-reflection coating was fabricated by electron-beam deposition system. In our research, the conversion efficiency was improved to 15.7% by using the photoelectrochemical oxidation method.
Sheng, Jhih-Syuan, and 盛致璿. "Study of Solar Cells Based on Ge and GaAs Materials." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/46845895572262126050.
Повний текст джерела高雄師範大學
物理學系
98
Study of Solar Cells Based on Ge and GaAs Materials Jhih-Syuan Sheng* Jung-Hui Tsai** Department of Physics, National Kaohsiung Normal University, Kaohsiung, Taiwan, R.O.C Abstract In this thesis, we simulated and analyze two kinds of homojunction solar cells based on Ge and GaAs materials by the SILVACO simulation program. First, we consider the characteristics of Ge homojunction solar cells with different emitter concentrations. η increases from 5.48 % to 8.64 % when the concentration is increased from 2 x 1016 to 2 x 1019 cm-3 and become saturated at 9.26 % as the concentration is larger than that of 2 x 1021 cm-3. Another, as seen from the relationship between conversion efficiency η and emitter thickness, η increase form 7.86% to 9.28% when the emitter thickness is increased from 200 to 15000 Å. In chapter 3, we analyze the characteristics of GaAs homojunction solar cells with different emitter concentrations. η value decreases from 15.01 % to 8.91 % as the concentration is increased from 2 x 1018 to 2 x 1022 cm-3. It is clear that Isc decreases with increasing emitter doping concentration and minority carrier lifetime becomes shorter, lead to η decreases quickly. On the other hand, for considering the effect of emitter thickness for GaAs solar cells, the conversion efficiency decreases form 15.05 % to 8.58 % as emitter thickness is increased from 500 to 15000 Å. This result can be attributed that the relatively small diffusion length of minority carriers in GaAs layers, resulting in the large amount of recombination in neutral-emitter region. * Author ** Advisor
Tsai, Jia-Ling, and 蔡佳霖. "Optimized Design of Back-Contact Thin-Film GaAs Solar Cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/vn8ukq.
Повний текст джерела國立交通大學
光電工程研究所
106
In recent years, breakthroughs of silicon-based solar cells adopt the concepts of back contacts and back junction. The design not only eliminates the shadowing caused by the front contact but also decreases the series resistance. If such a design is applied to GaAs, the material with the highest single-junction power conversion efficiency (PCE)[1, 2], it may be possible to enhance the power conversion efficiency further. However, only few experiments on back-contact GaAs solar cells have been conducted due to fabrication challenges. In this work, we aim to optimize the design parameters by employing a validated Sentaurus TCAD model, including the doping concentration, base thickness, length and pitch of back electrodes. Through current-voltage characteristics, we could determine the best cell performance with different material qualities and their correlation to design parameters. Our study shows that the optimized thickness and doping concentration of back-contact solar cells correspond to 1.4 ~1.7 um and 5×〖10〗^16 cm^(-3) for all material qualities. Compared to conventional GaAs solar cells, the back-contact device have a relatively short diffusion length and large dark current, but PCE is 1~2% higher due to the increment of short-circuit current. Moreover, we show that while the optical shadowing is eliminated in the back-contact design, the electrical shading still affects the cell performance and is sensitive to the electrode length and pitch. Consequently, our simulation shows that both the anode and pitch should be relatively narrow in order to mitigate the recombination loss above the anode region.
Wu, Chung-Hsien, and 吳崇賢. "Performance Investigation of Sub-Cells in InGaP/GaAs/Ge Triple-Junction Solar Cells." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/23276504555536741375.
Повний текст джерела國立臺灣海洋大學
電機工程學系
96
In this thesis, we demonstrate that a novel triple-junction solar cell structure, using the materials of Ge, GaAs and InGaP from bottom to top, simultaneously obtains three sets of pn junction to form the three sub-solar-cell with series shunt. In addition, the model of energy conversion efficiency has also been presented. According to tune the open circuit voltage and short circuit current every sub-solar-cell to find out the influence of output characteristics and the suitable operation point, we successfully solved the current mismatch owing to three sub-solar-cell with series shunt. We obtained the excellent energy conversion efficiency. This way is the Non-Destructive measurement.
張仕添. "Numerical Study on InGaP/GaAs Dual-Junction and InGaP/GaAs/InGaAs Triple-Junction Solar Cells." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/81234859975370333229.
Повний текст джерела國立彰化師範大學
光電科技研究所
97
ABSTRACT Being a green energy source, the development of solar cell technology has continuous advancement in recent years. The series-connected multi-junction solar cells based on the III-V semiconductor material system are proven to be attractive for many space and terrestrial applications in substituting for the conventional solar cells based on silicon. In this thesis, the properties of InGaP/GaAs dual-junction and InGaP/GaAs/InGaAs triple-junction solar cells are investigated numerically by using the APSYS simulation program. In order to markedly increase the sunlight-to-energy conversion efficiency, the thickness of each cell is modified to gain the matched short-circuit current. In chapter 1, the material properties and the development history of the solar cells are introduced. In chapter 2, the device physics of solar cells and the relevant physical parameters used in the APSYS software are mentioned. In chapter 3, based on an experimental InGaP/GaAs dual-junction solar cell, the concept of current matching is studied. By changing the layer thickness of the top cell, the photon current and conversion efficiency can be improved by current matching. Under the situation of AM0 and one sun, when the thickness of the top cell base layer changes from 0.55 µm to 0.4 µm, the conversion efficiency is improved by 3%. In chapter 4, the current matching for the InGaP/GaAs/InGaAs triple-junction solar cell is then investigated. By optimizing the layer thickness of the top and middle cells, the appropriate solar cell structure which possesses high sunlight-to-energy conversion efficiency is recommended. Under the situation of AM1.5G and one sun, when the base layer thicknesses of the top cell and middle layer are 0.4 μm and 1.5 μm, respectively, the photon current is matched and the conversion efficiency is improved by 2.3%. Under the situation of AM0 and one sun, when the base layer thicknesses of the top cell and middle layer are 0.3 μm and 1.7 μm, respectively, the conversion efficiency is improved by 4.2%. At AM1.5D and one sun, when the base layer thicknesses of the top cell and middle layer are 0.5 μm and 1.7 μm, respectively, the conversion efficiency is improved by 1.3%. Finally, a summary to the previous studies is provided in chapter 5.
Lin, Yu-Cheng, and 林昱成. "The Process Study of Back-Contact GaAs Thin-Film Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/39737447755528377283.
Повний текст джерела中原大學
電子工程研究所
104
For single junction solar cell, GaAs is an excellent material due to its material properties such as direct bandgap can effectively absorbing and emitting light, good radiation hardness and low temperature coefficient make GaAs solar cells extensively used for space applications and concentrated photovoltaic systems. Single-junction GaAs solar cells can be as high as 33.5% under AM1.5G illumination in theory. The high efficiency back-contact silicon solar cells have been extensively explored, and many designs of back-contact type have been suggested during the last 40 years. Cells can achieve potentially higher efficiency by moving all or part of the frontside electrodes to the rear of the device to eliminate shading losses. Whether silicon solar cells were made in the conventional type or in back-contacted structure, it always needs hundreds micrometers of active layers to absorb the visible light due to its indirect bandgap and lower absorption coefficient. Compared with silicon, GaAs solar cells can absorb 99% light in the few micrometers is more suitable for thin-film devices and back-contacted design. In this study, we started to numerically simulate the performance of back-contact GaAs solar cells by using our in-house developed program, and use the results to design the epitaxial structure and process flow, then we combine the epitaxial lift-off technique to transfer the GaAs epilayer from the GaAs substrate to the flexible substrate to realize a lightweight and flexible thin-film solar cells. And we measure the current-voltage characteristics and quantum efficiency to confirm the performance of solar cells, under AM1.5G illumination, the conversion efficiency can achieve 20.904% and current density is 25.420mA/cm2. After optimization the p-electrode spacing and the anti-reflection coating, the conversion efficiency is 21.104% and current density is 25.732 mA/cm2 . This approach brings the potential of back-contacted design to thin-film solar cells. With further investigation and optimization on this structure and combine GaAs substrate re-use process to achieve a low-cost, high-efficiency thin-film solar cell.
Li, Chia-Hao, and 黎家豪. "Study on Thin Film GaAs Solar Cells and Substrate Reused Technologies." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/9aqnkw.
Повний текст джерела國立中興大學
精密工程學系所
99
This thesis focuses on fabrication of thin-film solar cell via cross-shaped pattern epitaxial lift-off (CPELO) technology. The device performance of different recycled times thin-film GaAs solar cell will be discussed and compared. The cross-shaped pattern array is used to define cell size and provide the etch path of etchant solution. The AlAs sacrificial layer is etched by hydrofluoric acid etchant through the cross-shaped hole. The CPELO technique does not require a temporary carrier substrate to transfer the epilayers because the desired carrier substrate is directly deposited onto the backside of epilayers before the epitaxial lift-off process. The desired carrier, the electroplate nickel substrate, can be contacted directly to the epilayer without wax or low-viscosity epoxy. The release time of the 2-inch wafer with 1mm2 cell sizes is about 2 hours. After CPELO process, the separated GaAs substrate can be recycled via chemical cleaning. The substrate degradation after lift-off was investigated using atomic force microscopy (AFM). The surface roughness is about 0.30 nm for new wafers and 0.50nm, 1.36nm after first and second substrate reused. With the increased roughness, the thin-film solar cell reduced in open-circuit voltage (Voc) in one-sun AM 1.5G light source. The Voc of thin-film cell separated from new GaAs substrate is 0.95 V. Compared to thin-film cells separated from first and second recycled GaAs substrate are 0.76 V and 0.66 V, respectively. Reused GaAs substrate surface roughness will lead to reduce the quality of epitaxy layer and also deteriorate the thin-film cell efficiency.
Su, Yu-Chih, and 蘇裕智. "Characteristics of Thin-Film GaAs Solar Cells with Optical Selective Filter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/13776929558884419797.
Повний текст джерела國立交通大學
光電工程研究所
104
In 2013, Alta device, Inc. has successfully demonstrated thin-film GaAs single-junction solar cells with record power conversion efficiency (PCE) of 28.8% by using an epitaxial lift-off (ELO) technique to eliminate the backward spontaneous emission into the substrate[1]. In this work, we aim to further suppressing the spontaneous emission to the front side by adding a selective filter membrane on the thin-film GaAs solar cells. It can effectively reduce the dark current, and thus enhance the open-circuit voltage (Voc) of GaAs thin film solar cells. Regarding the fabrication of thin film GaAs solar cells using the ELO method, the epitaxial layers need to be soaked in the etching solution. Without proper protection, the process likely deteriorates the solar cell performance and lengthens the process time. Therefore, we use a wet chemical etch method to remove the substrate completely, followed by electroplating of Nickle on the back as the carrier. We can successfully manufacture flexible GaAs thin-film solar cells in one quarter of a four-inch wafer. Regarding the fabrication of selective filters, we design and deposit 12 pairs of titanium dioxide (TiO2) and silicon dioxide (SiO2) dielectric stacks, targeting at cutoff wavelengths of 795nm, 858nm, and 915nm. According to the experimental results, the net Voc of the thin-film cells with the 858nm and 915nm cutoffs increased by 0.8 and 3.3mV, respectively, compared to the devices before the deposition of the selective filters. Furthermore, we have successfully developed an optical model that combines a rigorous couple wave analysis (RCWA) and the photon recycling calculation developed by NREL to quantify the Voc enhancement for thin-film GaAs solar cells with different top structures[2]. According to our simulation results, the thin-film device with nearly ideal material quality exhibits a maximal Voc enhancement 42.6mV by introducing a selective filter with the 860nm cutoff. We conclude that light management using spectrally selective optical filter may be vital to pursuit the efficiency limit of high-quality thin-film GaAs solar cells in the near future.
Shih, Ching yu, and 石謦毓. "Numerical Study of GaAs-Based Dual Junction Quantum Dot Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/79369317880725751388.
Повний текст джерела國立交通大學
影像與生醫光電研究所
101
A novel combination of quantum dot intermediate band solar cell and dual-junction tandem cell is proposed and studied numerically. We built our device model by using MatlabR coding and commercial software SilvacoR and APSYSR. A proper inclusion of quantum-dot-related carrier absorption is adapted through modified extinction coefficient k, and effective band gap of the device. The final calculation shows the optimal efficiency enhancement is about 1.11 times of the non-quantum-dot embedded device. This design has great potential to realize a triple junction result with a dual-junction photovoltaic device.
Ho, Kuan-Ying, and 何冠穎. "Optimization of the PEDOT:PSS/SiNW Hybrid Solar Cells and All-Back-Contact GaAs Solar Cells with Two Dimensional Simulation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/54685960405502594190.
Повний текст джерела國立臺灣大學
光電工程學研究所
104
The poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)/silicon nanowire (SiNW) hybrid solar cell and the all-back-contact gallium arsenide (GaAs) solar cell are studied in this thesis. We used different simulation methods based on the characteristic of each solar cell to obtain the optical and electrical properties of each solar cell. After analyzing the electrical properties of the PEDOT:PSS/SiNW hybrid solar cell and the all-back-contact GaAs solar cell, further optimization is proposed, respectively. For the PEDOT:PSS/SiNW hybrid solar cell, a numerical model that capable of simulating the organic/inorganic hybrid solar cells was developed. Furthermore, a Gaussian distribution models of tail/interfacial states and trap states are addressed to present this characteristic when simulating the organic/inorganic hybrid solar cells. The 2D-FDTD model was used to model the optical field. After the simulation parameters are verified by fitting the current density-voltage (J-V) curve to the experimental results, the PEDOT:PSS/SiNW hybrid solar cell is optimized. The optimal structure is proposed with a p-type doping Si layer in the SiNW region adjoining to the PEDOT:PSS and an n-type doping Si layer at the rear Si layer near the bottom contact. The highest efficiency of 16.12% could be obtained after the optimization. For the GaAs solar cell, an all-back-contact is employed to the GaAs solar cell. By investigating the electrical properties of the all-back-contact GaAs solar cell, we are able to find the optimum structural design. A thicker base layer can reach a higher generation current, but it can also lead to a higher recombination. Therefore, the base layer thickness is suggested to be 1.5 um. For a wider n-contact width, a higher Jsc can be obtained, but the recombination at the p-n junction region becomes larger, which deteriorates the FF. Consequently, the n-contact width is recommended to be 600 um. The best efficiency up to 25.12% could be achieved with the suggested structure.
Chang, Kai-Fu, and 張凱富. "Junction Formation and Transport Mechanism in Hybrid n-GaAs/PEDOT:PSS Solar Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3x5k86.
Повний текст джерела國立交通大學
應用化學系碩博士班
105
In recent years the combination of inorganic semiconductor and organic polymer materials, usually named hybrid, has attracted a lot of attention due to simple and low temperature fabrication processes with relatively inexpensive cost. In this study, we investigated the interface junction formation properties of n-GaAs/PEDOT:PSS hybrid solar cells on planar substrates by varying the GaAs substrates doping concentrations. The photocurrent, dark saturation current and build-in potential at this hybrid interface are measured by varying n-GaAs doping concentrations. The work function and valence band edge of the polymer are extracted from ultraviolet photoelectron spectroscopy to construct the band diagram of the hybrid n-GaAs/PEDOT:PSS junction. The current-voltage characteristics were analyzed by using pn-junction and Schottky models. The experimental evidences suggested that the interface between n-GaAs and PEDOT:PSS is most likely a Schottky type junction and the current transport is governed by thermionic emission of majority carriers over a barrier.