Dissertations / Theses on the topic 'Hydrogen passivation'
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Chatterjee, Basab. "Hydrogen passivation of heteroepitaxial indium phosphide /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487947908403973.
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Jafari, A. H. "The effect of hydrogen on the passivation process of iron." Thesis, London Metropolitan University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278931.
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Wilkinson, Andrew Richard. "The optical properties of silicon nanocrystals and the role of hydrogen passivation /." View thesis entry in Australian Digital Program, 2006. http://thesis.anu.edu.au/public/adt-ANU20060202.111537/index.html.
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Wilkinson, Andrew Richard, and arw109@rsphysse anu edu au. "The Optical Properties of Silicon Nanocrystals and the Role of Hydrogen Passivation." The Australian National University. Research School of Physical Sciences and Engineering, 2006. http://thesis.anu.edu.au./public/adt-ANU20060202.111537.
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This thesis examines the optical properties of nanoscale silicon and the sensitization of Er with Si. In this context, it predominantly investigates the role of defects in limiting the luminescence of Si nanocrystals, and the removal of these defects by hydrogen passivation. The kinetics of the defect passivation process, for both molecular and atomic hydrogen, are studied in detail. Moreover, the optical absorption of Si nanocrystals and the effect of annealing environment (during nanocrystal synthesis) on the luminescence are investigated. The effect of annealing temperature and hydrogen passivation on the coupling (energy transfer) of Si nanocrystals to optically active centres (Er) is also examined.¶
The electronic structure of silicon-implanted silica slides is investigated through optical absorption measurements. Before and after annealing to form Si nanocrystals, optical absorption spectra from these samples show considerable structure that is characteristic of the particular implant fluence. This structure is shown to correlate with the transmittance of the samples as calculated from the modified refractive index profile for each implant. Due to the high absorption coefficient of Si at short wavelengths, extinction at these wavelengths is found to be dominated by absorption. As such, scattering losses are surprisingly insignificant.
To eliminate interference effects, photothermal deflection spectroscopy is used to obtain data on the band structure of Si in these samples. This data shows little variance from bulk Si
structure and thus little effect of quantum confinement. This is attributed to the dominance of
large nanocrystals in the absorption measurements.¶
The effect of annealing environment on the photoluminescence (PL) from silicon nanocrystals synthesized in fused silica by ion implantation and thermal annealing is studied as a function of annealing temperature and time. Interestingly, the choice of annealing environment (Ar, N2, or 5 % H2 in N2) is found to affect the shape and intensity of luminescence emission
spectra, an effect that is attributed both to variations in nanocrystal size and the density of defect states at the nanocrystal/oxide interface.¶
The passivation kinetics of luminescence-quenching defects, associated with Si nanocrystals in SiO2, during isothermal and isochronal annealing in molecular hydrogen are studied by time-resolved PL. The passivation of these defects is modeled using the Generalized Simple
Thermal model of simultaneous passivation and desorption, proposed by Stesmans. Values for the reaction-rate parameters are determined for the first time and found to be in excellent
agreement with values previously determined for paramagnetic Si dangling-bond defects (Pb type centers) found at planar Si/SiO2 interfaces; supporting the view that non-radiative recombination in Si nanocrystals is dominated by such defects.¶
The passivation kinetics of luminescence-quenching defects during isothermal and isochronal annealing in atomic hydrogen are studied by continuous and time-resolved PL. The kinetics are compared to those for standard passivation in molecular hydrogen and found to be
significantly different. Atomic hydrogen is generated using the alneal process, through reactions between a deposited Al layer and H2O or OH radicals in the SiO2. The passivation and desorption kinetics are shown to be consistent with the existence of two classes of nonradiative defects: one that reacts with both atomic and molecular hydrogen, and the other that reacts only with atomic hydrogen. A model incorporating a Gaussian spread in activation energies is presented that adequately describes the kinetics of atomic hydrogen passivation and dissociation for the samples.¶
The effect of annealing temperature and hydrogen passivation on the excitation cross-section and PL of erbium in silicon-rich silica is studied. Samples are prepared by co-implantation of Si and Er into SiO2 followed by a single thermal anneal at temperatures ranging from 800 to
1100 degrees C, and with or without hydrogen passivation performed at 500 degrees C. Using time-resolved PL, the effective erbium excitation cross-section is shown to increase by a factor of 3, while the number of optically active erbium ions decreases by a factor of 4 with increasing annealing temperature. Hydrogen passivation is shown to increase the luminescence intensity
and to shorten the luminescence lifetime at 1.54 micron only in the presence of Si nanocrystals. The implications of these results for realizing a silicon-based optical amplifier are also discussed.
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Yelundur, Vijay Nag. "Understanding and Implementation of Hydrogen Passivation of Defects in String Ribbon Silicon for High-Efficiency, Manufacturable, Silicon Solar Cells." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5271.
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Photovoltaics offers a unique solution to energy and environmental problems simultaneously. However, widespread application of photovoltaics will not be realized until costs are reduced by about a factor of four without sacrificing performance. Silicon crystallization and wafering account for about 55% of the photovoltaic module manufacturing cost, but can be reduced significantly if a ribbon silicon material, such as String Ribbon Si, is used as an alternative to cast Si. However, the growth of String Ribbon leads to a high density of electrically active bulk defects that limit the minority carrier lifetime and solar cell performance. The research tasks of this thesis focus on the understanding, development, and implementation of defect passivation techniques to increase the bulk carrier lifetime in String Ribbon Si in order to enhance solar cell efficiency. Hydrogen passivation of defects in Si can be performed during solar cell processing by utilizing the hydrogen available during plasma-enhanced chemical vapor deposition (PECVD) of SiNx:H films. It is shown in this thesis that hydrogen passivation of defects during the simultaneous anneal of a screen-printed Al layer on the back and a PECVD SiNx:H film increases the bulk lifetime in String Ribbon by more than 30 ?A three step physical model is proposed to explain the hydrogen defect passivation. Appropriate implementation of the Al-enhanced defect passivation treatment leads to String Ribbon solar cell efficiencies as high as 14.7%. Further enhancement of bulk lifetime up to 92 ?s achieved through in-situ NH3 plasma pretreatment and low-frequency (LF) plasma excitation during SiNx:H deposition followed by a rapid thermal anneal (RTA). Development of an optimized two-step RTA firing cycle for hydrogen passivation, the formation of an Al-doped back surface field, and screen-printed contact firing results in solar cell efficiencies as high as 15.6%. In the final task of this thesis, a rapid thermal treatment performed in a conveyer belt furnace is developed to achieve a peak efficiency of 15.9% with a bulk lifetime of 140 ?Simulations of further solar cell efficiency enhancement up to 17-18% are presented to provide guidance for future research.
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Atluri, Vasudeva Prasad 1959. "Hydrogen passivation of silicon(100) used as templates for low-temperature epitaxy and oxidation." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282650.
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Epitaxial growth, oxidation and ohmic contacts require surfaces as free as possible of physical defects and chemical contaminants, especially, oxygen and hydrocarbons. Wet chemical cleaning typically involves a RCA clean to remove contaminants by stripping the native oxide and regrowing a chemical oxide with only trace levels of carbon and metallic impurities. Low temperature epitaxy, T limits the thermal budget for the desorption of impurities and surface oxides, and can be performed on processed structures. But, silicon dioxide cannot be desorbed at temperatures lower than 800°C. Recently, hydrogen passivation of Si(111) has been reported to produce stable and ordered surfaces at low temperatures. Hydrogen can then be desorbed between 200°C and 600°C prior to deposition. In this work, Si(100) is passivated via a solution of hydrofluoric acid in alcohol (methanol, ethanol, or isopropyl alcohol) with HF concentrations between 0.5 to 10%. A rinse in water or alcohol is performed after etching to remove excess fluorine. This work investigates wet chemical cleaning of Si(100) to produce ordered, hydrogen-terminated, oxygen- and carbon-free surfaces to be used as templates for low temperature epitaxial growth and rapid thermal oxidation. Ion beam analysis, Tapping mode atomic force microscopy, Fourier transform infrared spectroscopy, Secondary ion mass spectroscopy, Chemical etching, Capacitance-voltage measurements and Ellipsometry are used to measure, at the surface and interface, impurities concentration, residual disorder, crystalline order, surface topography, roughness, chemical composition, defects density, electrical characteristics, thickness, and refractive index as a function of cleaning conditions for homoepitaxial silicon growth and oxidation. The wetting characteristics of the Si(100) surfaces are measured with a tilting plate technique. Different materials are analyzed by ion beam analysis for use as hydrogen standards in elastic recoil detection of hydrogen on sample surfaces. The results obtained in this study provide a quantitative optimization of passivation of Si(100) surfaces and their use as templates for low temperature epitaxy and rapid thermal oxidation. Ion beam analysis shows that the total coverage of H increases during passivation of Si(100) via HF in alcohol, while Fourier transform infrared spectroscopy indicates that more complex termination than the formation of simple silicon hydrides occurs.
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Jeong, Ji-Weon. "Hydrogen passivation of defects and rapid thermal processing for high-efficiency silicon ribbon solar cells." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15615.
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Valente, Damien. "Soudure directe silicium sur silicium : étude de procédés de passivation de l'interface." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4048/document.
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Ces travaux de thèse accompagnent le développement de nouvelles architectures d’interrupteurs monolithiques bidirectionnels en courant et en tension. L’une des voies technologiques proposées consiste à contrôler les propriétés électriques de l’interface de soudure Si-Si. Nous avons mis en évidence la nature complexe de l’activité électrique de l’interface avec l’existence d’un continuum d’états d’énergie au caractère recombinant. L’intégration d’une telle brique technologique nécessite alors la maîtrise de la passivation/décoration de l’interface par diffusion d’impuretés. La passivation des états d’interfaces par hydrogénation a montré une amélioration des propriétés électriques globales de l’interface de soudure avec une réduction de la dispersion des paramètres électriques. Une contamination contrôlée par diffusion de platine, nous a permis d’obtenir une désactivation, voire une compensation, du phosphore à l’interface, accompagnée d’une disparition des niveaux profonds1-lydrophobic silicon direct wafer bonding is an interesting way to realize new devices, espccia1lhen it could substitutc for double-side lithography or give access tu buried layers during process. This study goes with the design of a monolithic switch bidirectional in current and voltage for household appliances. We investigate the electrical properties of hydrophobic silicon wafer bonded interface. We have shown the interface is composed of several electronic defects, due to lattice deformations and residual contaminations, generating deep levels with recombinant properties. Finally, this study is focused on its electrical characterization and how to control its electrical activity. Hydrogenation and platinum diffusion are performed at Iow temperature and underline the possibility to restore the phosphorus biilk doping level. Therefore, an appropriate thermal treatment could be used to passivate a bonded interface without any bulk contamination
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Burrows, Michael Z. "Role of silicon hydride bonding environment in alpha-silicon hydrogen films for c-silicon surface passivation /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 152 p, 2008. http://proquest.umi.com/pqdweb?did=1654501711&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Crowe, Loretta L. "Reversible Attachment of Organic Dyes to Silica Surface Through Meijer-Type Hydrogen Bonding." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14058.
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In an approach to creating molecular-scale structures on glass surfaces via self assembly, a strongly-dimerizing ureido-[2-(4-pyrimidone)] (UPy) quadruple hydrogen-bonding array was chemically immobilized on silica surfaces by way of a triethoxysilane functionality. The unreacted surface silanols were then thoroughly passivated with a monofunctional organosilane, resulting in isolated UPy binding sites on the glass surface. These binding sites were found to selectively bind the strongly fluorescent perylenediimide (PDI) functionalized UPy molecules from solution, thus non-covalently linking the fluorophore to the surface. The association between the self-complementary molecules was exceptionally strong, both in solution and at the surface, such that effective hydrogen-bonding was retained after most solvent treatments. The binding was also reversible, however, so that washes with polar protic and dipolar aprotic solvents with high hydrogen-bonding capabilities, such as water, alcohols, and DMSO, resulted in the removal of the non-covalently bound fluorophore-tagged UPy.
The UPy:UPy dimer system was also investigated in solution, using pyrene intramolecular excimer formation as a monitor of the dissociation of the pyrene heterodimers into homodimers incapable of forming excimers at micromolar concentrations. In addition, the energy transfer process in solution between pyrene and perylenediimide fluorophores linked through UPy dimerization was studied, with the intention using FRET-based measurements on the surface at single-molecule levels in order to determine the distances between UPy binding sites. Energy transfer was found to occur, but the observed photophysical behavior was complicated by possible secondary processes, which steady-state fluorescence measurements were unable to elucidate.
The benefit of using this UPy system for attaching molecules to a surface lies in its reversibility of binding and versatility in manner of molecules which van be retained on the modified surface with a strong association. In this way molecular-scale features could conceivably be constructed on a surface by self-assembly, with the option of further chemical reactions to lock them in place, thus creating structures beyond the accessibility range of the conventional lithographic methods.
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Duportal, Malo. "Impact de la concentration en hydrogène sur les processus de dissolution et de passivation d’un acier inoxydable austénitique." Thesis, La Rochelle, 2020. http://www.theses.fr/2020LAROS024.
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De nombreux phénomènes sont susceptibles d’occasionner l’adsorption puis l’absorption d’hydrogène à la surface d’un matériau, modifiant ainsi ses propriétés intrinsèques de cœur comme de surface. En particulier, l’hydrogène introduit peut impacter les processus de corrosion, sujet encore que peu exploré et qui reste à interroger. Dans ce cadre, le présent travail a pour objet d’évaluer l’impact de l’absorption d’hydrogène sur les mécanismes de dissolution et passivation d’un acier inoxydable austénitique AISI 316L. Dans un premier temps, une caractérisation fine de la distribution d’hydrogène a été conduite. Les résultats obtenus ont montré un fort gradient de concentration permettant d’estimer le coefficient de diffusion ainsi que la concentration locale d’hydrogène. De plus, des techniques de caractérisation telles que le MET et la nano-indentation ont révélé que cette localisation induit une augmentation de la dureté, la formation de défauts de type dislocations, ainsi qu’une transformation locale de phase (γ→ε). Dans un deuxième temps, l’impact de l’absorption d’hydrogène sur les processus anodiques de l’alliage a été questionné. En particulier, les essais électrochimiques réalisés ont montré une augmentation des cinétiques dans le domaine anodique après absorption d’hydrogène. En présence du soluté le pic d’activité et la densité de courant passif sont sensiblement augmentés, et la résistance à la corrosion par piqûre est nettement altérée. Des analyses XPS ex-situ ont souligné le peu de modifications de la couche passive alors qu’une diminution significative de résistance a été clairement observée par EIS. Une augmentation des cinétiques de dissolution a clairement été établie par de analyses ICP, même si les poids respectifs de la dissolution et de l’oxydation de l’hydrogène n’ont pu être clairement quantifiés. Les modifications observées après chargement semblent en partie réversibles avec la désorption de l’hydrogène. Les résultats démontrent donc que l’hydrogène mobile est majoritairement responsable des effets observés, et que l’hydrogène piégé irréversiblement et les modifications métallurgiques induites par l’hydrogène et n’ont que peu d’effet sur les processus de corrosion même s’ils peuvent expliquer la non-réversibilité totale des effets observésDifferent processes can lead to hydrogen absorption on the surface of the materials and can decrease their inherent materials properties, especially their surface characteristics. Interactions between these modifications and corrosion processes have to be more thoroughly studied. In this context, this work aims to investigate the role of hydrogen absorption on the dissolution and passivation mechanisms of the AISI 316L. First, the total absorbed hydrogen concentration has been quantified after an electrochemical charging process. Then, we evaluated the different hydrogen states in the material and its distribution from surface to the bulk. Results suggest a strong concentration gradient and allows to estimate both an apparent coefficient of diffusion and a local hydrogen concentration. In addition, we observed that the local hydrogen increased hardness enhanced the dislocations density and induced an occasionally phase transformation to martensite (γ→ε). In the second time, the influence of hydrogen on anodic processes on the AISI 316L have been investigated. For that purpose, electrochemical tests have been conducted and show an increase of anodic kinetics after hydrogen absorption. Hydrogen induced an increase of the passive current density while the pitting resistance is widely degraded. XPS analyses attest of a similar passive layer (thickness and composition) before and after H-charging even though EIS results show a decrease of the resistance. Inductively Coupled Plasma showed that hydrogen promotes dissolution processes. The modifications induced by hydrogen are partially reversible with hydrogen desorption. Our results illustrate that mobile hydrogen is mainly responsible for the decrease of the properties and that trapped hydrogen and / or metallurgical modifications induced by electrochemical charging have few effects on the corrosion process even they highlight the partial non-reversibility of the observed effects
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Li, Da [Verfasser], and Christoph [Akademischer Betreuer] Brabec. "Hydrogen and Surface Passivation of Thin-film Crystalline Silicon Solar Cells on Graphite Substrates / Da Li. Gutachter: Christoph Brabec." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2015. http://d-nb.info/1080030972/34.
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Yelundur, Vijay Nag /. "Understanding and Implementation of Hydrogen Passivation of Defects in String Ribbon Silicon for High-Efficiency, Manufacturable, Silicon Solar Cells." Available online, 2003. http://etd.gatech.edu/theses/available/etd-11192003-164008/.
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Terry, Mason L. Photovoltaic & Renewable Energy Engineering UNSW. "Post???deposition processing of polycrystalline silicon thin???film solar cells on low???temperature glass superstrates." Awarded by:University of New South Wales. Photovoltaic and Renewable Energy Engineering, 2007. http://handle.unsw.edu.au/1959.4/30498.
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In polycrystalline silicon (pc-Si) thin-film solar cells, defect passivation is critical to device performance. Isoelectronic or covalently bonded impurities, hydrogenic, extended defects and defects with localized levels in the bandgap (deep level defects) are typically introduced during the fabrication of, and/or are inherent to, pc-Si thin-film solar cells. These defects dramatically affect minority carrier lifetimes. Removing and/or passivating these defects is required to maximize minority carrier lifetimes and is typically done through thermal annealing and passivation techniques. For pc-Si thin-film solar cells on low temperature glass superstrates, rapid thermal annealing (RTA) and hydrogen plasma passivation (hydrogenation) are powerful techniques to achieve effective removal and passivation of these defects. In this thesis, three silicon thin-film solar cells structures on low-temperature glass are subjected to variations in RTA high-temperature plateaus, RTA plateau times, and hydrogen plasma passivation parameters. These solar cells are referred to as ALICIA, EVA and PLASMA. By varying the RTA plateau temperature and time at plateau, the trade-off between extensive dopant diffusion and maximum defect removal is optimized. To reduce the density of point defects and to electrically activate the majority of dopants, an RTA process is shown to be essential. For all three of the thin-film solar cell structures investigated in this thesis, a shorter, higher-temperature RTA process provides the best open-circuit voltage (Voc). Extensive RTA plateau times cause excessive dopant smearing, increasing n = 2 recombination and shunt resistance losses. Hydrogenation is shown to be an essential step to achieve maximum device performance by `healing' the defects inherent to pc-Si thin-film solar cells. If the hydrogen concentration is about 1-2 times the density of oxygen in the cells as measured by secondary ion mass spectroscopy (SIMS), the cells seem to respond best to hydrogenation, with good resultant Voc and short-circuit for all cells investigated in this thesis. The effect of hydrogen passivation on the Voc is spectacular, typically increasing it by a factor of 2 to 3.5. Hydrogen de-bonding from repeated thermal treatments at increasing temperature provides a deeper understanding of what defects exist and the nature of the defects that limit the cell voltage. The variation in RTA and hydrogenation process parameters produces significant empirical insight into the effectiveness of RTA processes for point defect removal, dopant activation, point defect and grain boundary passivation, and impurity passivation. SIMS measurements are used to determine the impurities present in the cells' bulk and the amount of hydrogen available to passivate defects. From the results presented it appears that pc-Si thin-film solar cells on low-temperature glass are a promising, and potentially lower-cost, alternative to Si wafer based cells.
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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.
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Sandén, Martin. "Low-Frequency Noise in Si-Based High-Speed Bipolar Transistors." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3203.
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SALA, BEATRICE. "Contribution a l'etude de la corrosion du titane, de ses alliages et de certains aciers inoxydables en milieu aqueux, a haute temperature et sous pression." Orléans, 1987. http://www.theses.fr/1987ORLE2048.
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Application de l'electrochimie a haute temperature et sous pression illustree par trois cas de corrosion: 1) corrosion du titane et de ses alliages en milieu sulfurique 2) corrosion d'un acier a 13% de chrome en milieu carbonique; 3) corrosion d'aciers austeno-ferritique en milikeu carbonique contenant de l'hydrogene sulfure. Identification de differents facteurs permettant l'amelioration de la resistance a la corrosion de ces differents materiaux
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John, Sween. "A Study of the Synthesis and Surface Modification of UV Emitting Zinc Oxide for Bio-Medical Applications." Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc10990/.
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This thesis presents a novel ZnO-hydrogel based fluorescent colloidal semiconductor nanomaterial system for potential bio-medical applications such as bio-imaging, cancer detection and therapy. The preparation of ZnO nanoparticles and their surface modification to make a biocompatible material with enhanced optical properties is discussed. High quality ZnO nanoparticles with UV band edge emission are prepared using gas evaporation method. Semiconductor materials including ZnO are insoluble in water. Since biological applications require water soluble nanomaterials, ZnO nanoparticles are first dispersed in water by ball milling method, and their aqueous stability and fluorescence properties are enhanced by incorporating them in bio-compatible poly N-isopropylacrylamide (PNIPAM) based hydrogel polymer matrix. The optical properties of ZnO-hydrogel colloidal dispersion versus ZnO-Water dispersion were analyzed. The optical characterization using photoluminescence spectroscopy indicates approximately 10 times enhancement of fluorescence in ZnO-hydrogel colloidal system compared to ZnO-water system. Ultrafast time resolved measurement demonstrates dominant exciton recombination process in ZnO-hydrogel system compared to ZnO-water system, confirming the surface modification of ZnO nanoparticles by hydrogel polymer matrix. The surface modification of ZnO nanoparticles by hydrogel induce more scattering centers per unit area of cross-section, and hence increase the luminescence from the ZnO-gel samples due to multiple path excitations. Furthermore, surface modification of ZnO by hydrogel increases the radiative efficiency of this hybrid colloidal material system thereby contributing to enhanced emission.
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Defresne, Alice. "Amélioration de la passivation de cellules solaires de silicium à hétérojonction grâce à l’implantation ionique et aux recuits thermiques." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS533/document.
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Les cellules solaires à hétérojonction a-Si:H/c-Si atteignent un rendement record de 24.7% en laboratoire. La passivation de la surface du c-Si est la clé pour obtenir de hauts rendements. En effet, la brusque discontinuité de la structure cristalline à l'interface amorphe/cristal induit une forte densité de liaisons pendantes créant une grande densité de défauts dans la bande interdite. Ces défauts sont des centres de recombinaison pour les paires électron-trou photogénérées dans le c-Si. Différentes couches diélectriques peuvent être utilisées pour passiver les wafers dopés n et dopés p : (i) le SiO₂ réalisé par croissance thermique, (ii) l’Al₂O₃ déposé par ALD, (iii) le a-SiNₓ:H et l’a-Si:H déposés par PECVD. La couche de passivation la plus polyvalente est a Si:H puisqu’elle peut passiver aussi bien les wafers dopés n que ceux dopés p. De plus sa production est peu coûteuse en énergie car sa croissance est réalisée à une température d’environ 200°C. L’inconvénient de cette couche de passivation est que lorsqu’elle est dopée p elle ne supporte pas des températures supérieures à 200°C, en raison de l’exodiffusion des atomes d’hydrogène qu’elle contient. Cependant, afin d'avoir un bon contact électrique, TCO et électrodes métalliques, il est souhaitable de recuire à plus haute température (entre 300°C et 500°C). Nous avons implanté des ions Argon de façon contrôlée dans des précurseurs de cellules solaires à des énergies comprises entre 1 et 30 keV, pour contrôler la profondeur à laquelle nous créons les défauts. En variant la fluence entre 10¹² Ar.cm⁻² et 10¹⁵ Ar.cm⁻² nous contrôlons la concentration de défauts créés. Nous montrons qu’une implantation à une énergie de 5 keV avec une fluence de 10¹⁵ Ar.cm⁻² n’est pas suffisante pour endommager l’interface a-Si:H/c-Si. La durée de vie effective des porteurs minoritaires mesurée par photoconductance (temps de décroissance de la photoconductivité) passe de 3 ms à 2,9 ms après implantation. En revanche les implantations à 10 keV, 10¹⁴ Ar.cm⁻² ou à 17 keV, 10¹² Ar.cm⁻² sont suffisantes pour dégrader la durée de vie effective de plus de 85%. Suite aux implantations les cellules solaires ont subi des recuits sous atmosphère contrôlée à différentes températures et ce jusqu’à 420°C. Nous avons découvert que le recuit permet de guérir les défauts introduits par l’implantation. Mais surtout, dans certains cas, d’obtenir des durées de vie après implantation et recuit supérieures aux durées de vies initiales. En combinant l’implantation ionique et les recuits, nous conservons de bonnes durées de vies effectives des porteurs de charges (supérieures à 2 ms) même avec des recuits jusqu’à 380°C. Nous avons utilisé une grande variété de techniques telles que la photoconductance, la photoluminescence, l’ellipsométrie spectroscopique, la microscopie électronique en transmission, la Spectroscopie de Masse d’Ions Secondaires, la spectroscopie Raman et l’exodiffusion de l’hydrogène pour caractériser et analyser l’ensemble des résultats et phénomènes physico-chimique intervenant dans la modification des précurseur de cellules solaires. Nous discutons ici de plusieurs effets tels que l’augmentation de la durée de vie et la tenue en température par la conservation de l’hydrogène dans la couche de silicium amorphe et ceci même après les recuits. Cette conservation peut s’expliquer par l’augmentation du nombre de liaisons Si-H au sein du silicium amorphe et par la formation de cavités lors de l’implantation. Durant les recuits l’hydrogène qui diffuse est piégé puis libéré par les cavités et/ou les liaisons pendantes, ce qui limite son exo-diffusion et le rend de nouveau disponible pour la passivation des liaisons pendantesA-Si:H/c-Si heterojunction solar cells have reached record efficiencies of 24.7%. The passivation of c-Si is the key to achieve a high-efficiency. Indeed, the abrupt discontinuity in the crystal structure at the amorphous/crystal interface induces a high density of dangling bonds creating a high density of defects in the band gap. These defects act as recombination centers for electron-hole pairs photogenerated in c-Si. Several dielectric layers can be used to passivate n-type and p-type wafers: (i) SiO₂ produced by thermal growth, (ii) Al₂O₃ deposited by ALD, (iii) a-SiNₓ:H and a-Si:H deposited by PECVD. The most versatile passivation layer is a-Si: H because it is effective for both p-type and n-type wafers. In addition, this process has a low thermal budget since the deposition is made at 200°C. The drawback of this passivation layer, in particular when p-type doped, is that it does not withstand temperatures above 200°C. However, in order to have a good electrical contact, TCO and metal electrodes require high temperature annealing (between 300°C and 500°C).We implanted Argon ions in solar cell precursors with energies between 1 and 30 keV, which allows to control the depth to which we are creating defects. By varying the fluence between 10¹² Ar.cm⁻² and 10¹⁵ Ar.cm⁻² we control the concentration of defects. We show that implantation with an energy of 5 keV and a fluence of 10¹⁵ Ar.cm⁻² is not sufficient to damage the a-Si:H/c-Si interface. The effective lifetime of the minority charge carriers, measured using a photoconductance technique (decay time of photoconductivity), decreases only from 3 ms to 2.9 ms after implantation. On the other hand the implantations at 10 keV, 10¹⁴ Ar.cm⁻² or at 17 keV, 10¹² Ar.cm⁻² are sufficient to degrade the effective lifetime by more than 85%.Following implantation the solar cells have been annealed in a controlled atmosphere at different temperatures and this up to 420°C. We show that annealing can heal the implantation defects. Moreover, under certain conditions, we obtain lifetimes after implantation and annealing greater than the initial effective lifetime. Combining ion implantation and annealing leads to robust passivation with effective carrier lifetimes above 2 ms even after annealing our solar cell precursors at 380°C. We used a large variety of techniques such as photoconductance, photoluminescence, spectroscopic ellipsometry, Transmission Electron Microscopy, Secondary Ion Mass Spectrometry, Raman spectroscopy and hydrogen exodiffusion to characterize and analyze the physico-chemical phenomena involved in the modification of solar cells precursors. We discuss here several effects such as the increase of the effective lifetime and the temperature robustness by the preservation of hydrogen in amorphous silicon layer and this even after annealing. This hydrogen preservation can be explained by the increase of the number of Si–H bonds in amorphous silicon and the formation of cavities during implantation. In the course of annealing the hydrogen which diffuses is trapped and then released by cavities and dangling bonds, which limits its exodiffusion and makes it available for dangling bonds passivation
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Gaufrès, Aurélien. "Élaboration de carbure de silicium amorphe hydrogéné par PECVD : Optimisation des propriétés optiques, structurales et passivantes pour des applications photovoltaïques." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0005.
Full textAbstract:
Notre étude concerne la mise en place et le développement de dépôts de carbure de silicium amorphe hydrogéné (a-SiCx:H) à basse température (370°C), par voie PECVD, sur un réacteur PECVD semi-industriel à faible fréquence (440 kHz). Les propriétés chimiques, optiques et de passivation de surface des couches déposées sont analysées et l’impact du changement des débits de gaz précurseurs (silane et méthane) est aussi étudié. La possibilité d’utiliser le a-SiCx:H comme couche anti-reflet en face avant d’une cellule solaire est envisagée. Bien que l’indice de réfraction d’une couche riche en carbone soit en accord avec la condition de lame quart-d’onde requise pour une couche anti-reflet, le coefficient d’extinction est trop élevé en raison de la proportion significative de silicium dans la couche. Cette absorption peut être atténuée par l’incorporation d’azote dans la couche (a-SiCxNy:H). En revanche, la passivation de surface s’améliore lorsque la quantité de silane augmente. La plus faible vitesse de recombinaison de surface atteinte sur les échantillons après dépôt est de 10 cm.sOur study deals with the deposition of amorphous hydrogenated silicon carbide (a- SiCx:H) at low temperature (370°C), by PECVD technique, using a semi-industrial lowfrequency PECVD reactor (440 kHz). The deposited films are analyzed for chemical, optical and surface passivation properties, and the impact of the gas flow parameters (silane and methane) is studied. The possible use of a-SiCx:H as an antireflective coating at the front side of solar cells is investigated. Although the refractive index for high carbon concentration could be in agreement with the demand of quarter-wave layer for antireflective coating, the extinction coefficient remains too high due to a significant silicon content in the material. This absorption can be attenuated by incorporating nitrogen in the layer. However, the surface passivation improves with the silane proportion. The lowest surface recombination velocity of an as-deposited samples is about 10 cm.s
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Sutter, Eliane. "Contribution a l'etude de la reactivite de la surface du titane en solution acide." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13131.
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Lamirault, Sylvie. "Comportement du cuivre dans les melanges hf-mf (m = k ou nh : :(4)) fondus utilises pour l'obtention electrolytique du fluor." Paris 6, 1987. http://www.theses.fr/1987PA066467.
Full textAbstract:
Etude thermodynamique et cinetique de la corrosion electrochimique dans les melanges hf-mf(m=k ou nh::(4)) du cuivre metal entrant, soit pur, soit sous forme d'alliage (monel) dans la construction des cellules industrielles d'electrolyse. Mise en evidence de la formation d'une couche de fluorure de cuivre passivante. Evaluation de l'epaisseur limite de la couche. Etablissement de l'influence de la densite de courant sur le caractere passivant de la couche formee. Proposition d'un mecanisme de corrosion du cuivre
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Lin, Chia-Te, and 林佳德. "Hydrogen Passivation of Crystalline Silicon Solar Cell." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/31178641818228803238.
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"Grain Boundary Passivation of Multicrystalline Silicon Using Hydrogen Sulfide as a Sulfur Source." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.27513.
Full textAbstract:
abstract: Hydrogen sulfide (H2S) has been identified as a potential ingredient for grain boundary passivation of multicrystalline silicon. Sulfur is already established as a good surface passivation material for crystalline silicon (c-Si). Sulfur can be used both from solution and hydrogen sulfide gas. For multicrystalline silicon (mc-Si) solar cells, increasing efficiency is a major challenge because passivation of mc-Si wafers is more difficult due to its randomly orientated crystal grains and the principal source of recombination is contributed by the defects in the bulk of the wafer and surface.
In this work, a new technique for grain boundary passivation for multicrystalline silicon using hydrogen sulfide has been developed which is accompanied by a compatible Aluminum oxide (Al2O3) surface passivation. Minority carrier lifetime measurement of the passivated samples has been performed and the analysis shows that success has been achieved in terms of passivation and compared to already existing hydrogen passivation, hydrogen sulfide passivation is actually better. Also the surface passivation by Al2O3 helps to increase the lifetime even more after post-annealing and this helps to attain stability for the bulk passivated samples. Minority carrier lifetime is directly related to the internal quantum efficiency of solar cells. Incorporation of this technique in making mc-Si solar cells is supposed to result in higher efficiency cells. Additional research is required in this field for the use of this technique in commercial solar cells.Dissertation/Thesis
Masters Thesis Electrical Engineering 2014
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Zhang, Yi. "Modeling hydrogen diffusion for solar cell passivation and process optimization." Thesis, 2002. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2002-024.
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Santos, Paulo David Rodrigues. "Hydrogen passivation of recombination centers in silicon: density functional theory calculations." Doctoral thesis, 2019. http://hdl.handle.net/10773/29222.
Full textAbstract:
The evolution of the solar cell market has motivated significant advances in
the search of cheaper and more efficient materials. Crystalline silicon is one
of the most dominant materials for photovoltaic (PV) applications, with one
of the best cost-efficiency relations available. However, there is room for improvement
with the elimination or passivation of many defects that can trap
positive and negative charge carriers (holes and electrons) followed by their
recombination. Transition metal (TM) impurities are among the most dangerous
recombination centers contributing severely to the loss of the efficiency
of the solar cells. While some of them can be driven to form large precipitates
in the grain boundaries of the crystals, opening some "impurity-free"paths,
others, due to their low diffusivity, will stay isolated or in the form of small aggregates.
Hydrogen passivation is considered to be an important solution for
the mitigation of the electrical activity associated to these defects. The main
goal of this thesis is to study the interaction between hydrogen and several
defects originating either from transition metals or other common impurities
in solar silicon by means of first-principles calculations based on the density
functional theory. These calculations were done with the application of the
generalized gradient approximation (GGA) for the exchange and correlation
potentials, employing 216 and 512-Si supercells. The issues addressed here
can be divided in three parts: the calculation of the electronic structure of isolated
transition metal impurities in silicon (chapter 3), the interaction between
hydrogen and these metallic impurities (chapters 4 and 5), and the interaction
between hydrogen and defects originating from common impurities such
as Carbon and Oxygen (chapter 6). The main results of this thesis can be
summarized as follows: (i) in agreement with previous models and with the
available experimental data, slow-diffusing transition metals from groups IV, V
and VI are stable at the tetrahedral interstitial sites, producing significant electronic
activity, with multiple deep donor levels, and, in some cases, acceptor
levels; (ii) the effectiveness of hydrogen passivation of the electronic activity
arising from transition metal impurities is limited by the doping type of the material:
while in n-type silicon the formation of metallic-hydrogen complexes is
likely, in p-type this is not possible to observe due the long range electrostatic
repulsion between positively charged hydrogen and metallic impurities; (iii)
these metallic-hydrogen complexes display appreciably less electronic activity
than the isolated metallic impurities and, in some cases, full passivation is
achieved; (iv) the interaction between hydrogen and typically inert impurities
such as carbon and oxygen leads to the formation of a defect with multiple
stable configurations that can work both as an electron or a hole trap, leading
to the recombination.A evolução do mercado de células solares tem motivado avanços significativos na busca de materiais mais baratos e eficientes. O silício cristalino é um dos materiais mais dominantes para aplicações fotovoltaicas (PV), com uma das melhores relações custo-eficiência disponíveis. No entanto, há espaço para melhorias com a eliminação ou passivação de muitos defeitos capazes de capturar portadores de carga positivos e negativos (lacunas e eletrões), seguindo-se a sua recombinação. Impurezas como os metais de transição são alguns dos centros de recombinação mais eficazes que contribuem drasticamente para a perda da eficiência das células solares. Enquanto alguns deles podem ser levados a formar precipitados nos limites de grão dos cristais, abrindo assim alguns caminhos "livres de impurezas", outros, devido à sua baixa difusividade, permanecem isolados ou na forma de pequenos agregados. A passivação com hidrogénio é considerada uma solução importante para mitigar a atividade elétrica associada a esses defeitos. O objetivo principal desta tese é o estudo da interação do hidrogénio com múltiplos defeitos que têm a sua origem tanto em impurezas de metais de transição como em outras impurezas comuns em silício para aplicações fotovoltaicas através de cálculos de primeiros princípios baseados na teoria do funcional da densidade. Estes cálculos foram realizados com a aplicação da aproximação do gradiente generalizado (GGA) para os potenciais de correlação e troca utilizando super-células de silício de 216 ou 512 átomos. Os assuntos aqui abordados podem-se dividir em três partes: O cálculo da estrutura electrónica de impurezas de metais de transição isoladas em silício (capítulo 3), a interação entre o hidrogénio e essas impurezas (capítulos 4 e 5) e a interação entre hidrogénio e defeitos que têm a sua origem em impurezas comuns tais como o carbono e o oxigénio. Os resultados principais obtidos nesta tese podem ser resumidos do seguinte modo: De acordo com os modelos existentes e os resultados experimentais disponíveis, metais de transição dos grupos IV, V e VI são estáveis em posições intersticiais com simetria tetraédrica, produzindo atividade electrónica significativa, com múltiplos níveis dadores profundos e, em alguns casos, níveis aceitadores; a eficácia da passivação por hidrogénio da atividade electrónica produzida por impurezas de metais de transição é limitada pelo tipo de dopagem do material: enquanto que em silício tipo n a formação de complexos de metal-hidrogénio é possível, no caso de silício tipo p isto não se observa devido à repulsão eletrostática a longa distância entre o hidrogénio e as impurezas metálicas, uma vez que, para este tipo de dopagem, em equilíbrio termodinâmico, ambos se encontram no estado de carga positivo. Estes complexos de metal-hidrogénio apresentam significativamente menos atividade electrónica do que metais isolados, e, em alguns casos, existe uma passivação completa do defeito; a interação entre o hidrogénio e impurezas tipicamente inertes como o carbono e oxigénio resulta na formação de um defeito com múltiplas configurações estáveis e que é capaz de funcionar como um centro de captura tanto para eletrões como lacunas, resultando na sua recombinação.
Programa Doutoral em Engenharia Física
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"Phosphorous diffusion and hydrogen passivation of polycrystalline silicon for photovoltaic cells." Thesis, 2012. http://hdl.handle.net/10210/5415.
Full textAbstract:
M.Sc.Techniques for the fabrication of polycrystalline silicon solar cells have advanced in recent years with efficiencies exceeding 17%. The major advantage of polycrystalline silicon is its low cost relative to single-crystalline silicon. The disadvantage is the significantly smaller minoritycarrier bulk diffusion length and inhomogeneous nature of the material. These two drawbacks are due to the presence of grain boundaries as well as high concentrations of dislocations and other physical and chemical defects. In this study the experimental conditions were determined to fabricate solar cells on polycrystalline silicon substrates. The controlled diffusion of phosphorous into silicon and subsequent evaluation of the doped layers (by spreading resistance profiling and chemical staining) were important aspects of this study. From these results the diffusion parameters (i.e. temperature and reaction times) could be optimized in order to improve the solar cell output parameters. Additional material improvement (increase in surface- and bulk minority carrier lifetimes) was demonstrated by the hydrogen passivation of electrically active defects in polycrystalline silicon. However. measurements on hydrogenated silicon samples also indicated that excess passivation can result in surface damage and subsequent reduction in the minority carrier lifetimes. Preliminary solar cells were fabricated on polycrystalline silicon with efficiencies ranging between 0.5 and 6% (total area = 16 cm2).
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Hsieh, Ming-Hung, and 謝明宏. "Study of Silicon Solar Cell Efficiency Enhancement by Using Hydrogen Passivation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/91668732212287857591.
Full textAbstract:
碩士國立交通大學
理學院碩士在職專班應用科技學程
99
The main purpose of this thesis is to study the influence of hydrogen passivation on silicon solar cell conversion efficiency by applying hydrogen plasma to silicon solar cells with different efficiency and under different temperature condition. Improvements of both the electrical characteristics and efficiency of silicon solar cells are observed after the hydrogen passivation process. Our experimental results show the highest conversion efficiency improvement of the silicon solar cell is raised by 0.95%. The influence of the hydrogen passivation on the conversion efficiency is close related to the reduction of silicon solar cell series resistance. It is because that the hydrogen affects the current path from the Ag crystals into the bulk of the Ag finger, reducing the metal oxides in the glass layer and increasing current tunneling probability in the Si. Therefore, it decreases overall resistivity of silicon solar cell devices under test and leads to the increase of the conversion efficiency.
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Lian, Tsu-Ting, and 連姿婷. "Silicon Nano-oxidation by AFM－Crystal Orientation and Hydrogen Passivation Effect." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/53322045493438858807.
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Chang, Wei-Song, and 張維松. "Study of hydrogen plasma passivation effects on low-temperature polysilicon TFT's." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/94660206192688671119.
Full textAbstract:
碩士國立交通大學
電子研究所
82
The reduction of trap-state density by plasma hydrogenation of n-channel polysilicon thin film transistors (poly-Si TFT's) fabricated using a maximum temperature of 600(C has been studied. Hydrogenated devices have a mobility of 32 cm2/Vsec,a threshold voltage of ~3V, and a maximum ON/OFF current ratio of 1.8e6.Trap- state density decreases to about 9% of the value of the as-fabricated devices, concomitant with the reduction of threshold voltage.In addition, the effect and kinetics of the hydrogen passivation on polysilicon thin film transistors were also investigated. Based on the response of device parameters with the progress of hydrogenation, two types of defects can be distinguished from the difference in the passivation rate.
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Dhar, Sarit. "Nitrogen and hydrogen induced trap passivation at the SiO₂/4H-SiC interface." Diss., 2005. http://etd.library.vanderbilt.edu/ETD-db/available/etd-02222005-122500/.
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Han-YinLiu and 劉漢胤. "Investigation of Hydrogen Peroxide Passivation on AlGaN/GaN High Electron Mobility Transistors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/83063215784788788288.
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Gorka, Benjamin [Verfasser]. "Hydrogen passivation of polycrystalline Si thin film solar cells / vorgelegt von Benjamin Gorka." 2010. http://d-nb.info/101182471X/34.
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Lee, Hsin Ju, and 李信儒. "The Study of Hydrogen (Oxygen) Passivation Effects on Metal (Al(1%Si)) / Polysilicon Contact Systems." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/50361823209357134367.
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Kang, Jingxuan. "Poly Silicon on Oxide Contact Silicon Solar Cells." Thesis, 2019. http://hdl.handle.net/10754/652926.
Full textAbstract:
Silicon photovoltaic (PV) is a promising solution for energy shortage and environmental pollution. We are experiencing an era when PV is exponentially increasing. Global cumulative installation had reached 380 GW in 2017. Among which, silicon-based PV productions share more than 90% market. Performance of the first two-generation commercial popular silicon solar cells - Al-BSF and PERC - are limited by metal/Si contacts, where interface defects significantly reduce the open-circuit voltage. In this context, full-area passivation concepts are proposed for c-Si solar cells, with expectation to enhance the efficiency via reducing carrier recombination loss at the contact regions. In this thesis, poly silicon on oxide (POLO) passivating contact is developed for high efficiency c-Si solar cells. We unveiled the working mechanisms of POLO cells and then optimized the device performance based on our conclusion.
We use boiling nitric acid to oxidize c-Si surface, which is of significance to determine the POLO working mechanisms. Phosphorus and boron doped silicon films are deposited by plasma enhanced vapor deposition (PECVD) or low-pressure vapor deposition (LPCVD) followed by high temperature (>800°C) annealing. SiOx structural evolution process under different annealing temperature was observed and the corresponding effects on passivation have been elucidated. The carrier transport mechanisms in the POLO contact annealed at high temperature, e.g. 800°C 900°C, were explored. We unveil that carrier transport in POLO structure is a combination of tunneling and pinhole transport, but dominant at varied temperature regions.
Phosphorus-doped n-type POLO contact is optimized by several parameters, such as doping concentration, film thickness, annealing temperature, film deposition temperature, film relaxation time during annealing process, etc. We successfully obtained minority carrier lifetime over 10ms and contact resistivity lower than 30 mΩ·cm2. Boron-doped p-type POLO contact is also optimized by changing the doping concentration and annealing temperature. Finally, further hydrogen passivation is applied to enhance p-type POLO contact passivation, achieving an iVoc>690 mV, J0 <5 fA/cm2 and contact resistivity 1.3 mΩ·cm2. With the optimized n-type and p-type POLO contacts, an efficiency over 18% is achieved on n-type c-Si solar cells with a flat front surface.
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Spiegel, Markus [Verfasser]. "Microwave induced remote hydrogen plasma (MIRHP) passivation of multicrystalline silicon solar cells / vorgelegt von Markus Spiegel." 1998. http://d-nb.info/95678819X/34.
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GIAN, HE-GING, and 錢河清. "Study of siiicon surface damage induced with ar ion implantation and its passivation by atomic hydrogen." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/22111101962852339606.
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Bassett, Robert S. "Characterization of hydrogen plasma for polycrystalline silicon passivation in a large area, inductively-coupled plasma reactor." 1997. http://catalog.hathitrust.org/api/volumes/oclc/39266171.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1997.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 90-91).
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Chen, Kuan-Yu, and 陳冠宇. "The Effect of Hydrogen Reducing and Sulfur Passivation on the Cu(In,Ga)Se2 Solar Cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/73pemj.
Full textAbstract:
碩士國立交通大學
電子工程學系 電子研究所
102
In this thesis, we used the CIGS thin films of selenization by CIG and Se vapor mixed the different contents of hydrogen. And then the CIGS thin films were placed into chemical solutions to carry out the experiments of surface passivation. We studied the effects of different contents of hydrogen and different type of solutions on CIGS thin film characteristics. SEM was used to observe the film’s morphology, crystalline phase and composition of the CIGS layer were determined by XRD and EDS analysis, and XPS was used to analyze the elements composition of the CIGS thin films surface. Afterwards, we completed solar cell, from top to bottom its structure was sequentially Al/AZO/ZnO/CdS/CIGS/Mo/SLG. The effective area of solar cell device was 0.38cm2. And solar spectrum simulate measurement system was used to measure device conversion efficiency, open circuit voltage, short-circuit current and fill factor etc. parameters. The experiment results indicated that the CIGS thin films selenized by CIG and Se vapor mixed 15% hydrogen and then the CIGS thin films was passivated by thioacetamide (TAM) liquid. After the above CIGS thin films were produced solar cell, it had the best efficiency. Its conversion efficiency of 11.8% can be achieved.
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ZHANG, YI-MIN, and 張毅敏. "Influence of Hydrogen passivation on the infrared spectra of p-type Hg0.8Cd0.2Te and B-ion implanted Hg0.8Cd0.2Te." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/71777669935893170047.
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Chen, Da-Ching, and 陳達慶. "Characterization of Sulfur、Fluorine and Hydrogen Passivation on Titanium Oxide prepared by Atomic Layer Deposition on Gallium Arsenide." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/2rx23u.
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碩士國立中山大學
電機工程學系研究所
97
Due to the high electron mobility compared with Si, III-V compound semiconductors (GaAs) has been applied widely for high-speed devices. The titanium oxide (TiO2) has not only has high dielectric constant but has well lattice match with GaAs substrate. Therefore, the high-k material TiO2 was chosen to be the gate oxide in this study. The major problem of III-V compound semiconductors is known to have poor native oxide on it and leading to the Fermi level pinning at the interface between oxide and semiconductor. The C-V stretch-out phenomenon can be observed and the leakage current is high. The surface passivation of GaAs with (NH4)2Sx treatment (S-GaAs) can prevent it from oxidizing after cleaning and improve the interface properties. In order to passivate the grain boundary of polycrystalline ALD-TiO2 film and the interface state, the fluorine from liquid-phase- deposited SiO2 solution can achieve the goal effectively. In addition, the post-metallization annealing (PMA) is another efficiency way to improve the ALD-TiO2 film quality. The mechanism of PMA process is the reaction between the aluminum contact and hydroxyl groups existed on TiO2 film surface. Then the active hydrogen is produced to diffuse through the oxide and passivate the oxide traps.
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"Temperature Dependent Qualities of Amorphous Silicon and Amorphous Silicon Carbide Passivating Stacks." Master's thesis, 2016. http://hdl.handle.net/2286/R.I.40230.
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abstract: Layers of intrinsic hydrogenated amorphous silicon and amorphous silicon carbide
were prepared on a polished, intrinsic crystalline silicon substrate via plasma-enhanced chemical vapor deposition to simulate heterojunction device relevant stacks of various materials. The minority carrier lifetime, optical band gap and FTIR spectra were observed at incremental stages of thermal annealing. By observing the changes in the lifetimes the sample structure responsible for the most thermally robust surface passivation could be determined. These results were correlated to the optical band gap and the position and relative area of peaks in the FTIR spectra related to to silicon-hydrogen bonds in the layers. It was found that due to an increased presence of hydrogen bonded to silicon at voids within the passivating layer, hydrogenated amorphous silicon carbide at the interface of the substrate coupled with a hydrogenated amorphous silicon top layer provides better passivation after high temperature annealing than other device structures.Dissertation/Thesis
Masters Thesis Electrical Engineering 2016
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Chen, Liang-Yi, and 陳兩儀. "The study of Passivation Effect on the Solar Cell with Single and Multi-Crystalline by the Hydrogen Forming Gas." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/63812123133641147817.
Full textAbstract:
碩士國立臺灣海洋大學
電機工程學系
95
Abstract In this thesis, there are two parts. First, check if H2 forming gas method can improve the performances of single and multi crystalline silicon (Si) solar cell. H2 forming gas is used in the producing process of microelectronics and photovoltaic device. Second, check the relationship between the diffusion temperature and conversion efficiency in the phosphorus diffusion, on the Si solar cell application. In the experiment, the current- voltage (I-V) curve of crystalline silicon solar cells are recorded by I-V tester, to check the conversion efficiency (η), open circuit voltage (Voc), short circuit current (Isc), and fill factor (FF) reflecting to the adoption of H2 forming gas. Above are important parameters to the performance of solar cell. These changes regarding to different H2 forming gas time are analyzed afterward. It can be seen that H2 forming gas treatment can enhance the performance of both single-crystalline and multi-crystalline Si solar cells; especially for multi-crystalline Si for 40 minutes. The conversion efficiency (η) can be increased by 2% and the entire efficiency can be improved by 16% (2/12.5). In addition to I-V tester, WT-2000 conducts light-beam induced current (LBIC) to record the change of internal quantum efficiency (IQE), which can reflect to the adoption of H2 forming gas method. Overall, H2 forming gas method stands out by its simple and low-cost process. The other part is phosphorus diffusion. In this thesis we aim to formula the equation of diffusion temperature, sheet resistance, and conversion efficiency. Besides, with the scanning electron microscope (SEM) and UV spectrum, the influence of surface texture can be observed. The relationship between diffusion temperature and sheet resistance also conversion efficiency can be figured out in the experiment. Besides, with the scanning electron microscope (SEM) and UV spectrum, the influence of surface texture can be observed. The relationship between diffusion temperature and sheet resistance also conversion efficiency can be figured out in the experiment. Keyword: H2 forming gas, crystalline silicon, solar cell, phosphorus diffusion, surface texture.