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Article
The Staebler-Wronski Effect: New Physical Approaches and Insights as a Route to Reveal its Origin
In the recent years more and more theoretical and experimental evidence have been found that the hydrogen bonded to silicon in dense hydrogenated amorphous silicon (a-Si:H) predominantly resides in hydrogenate...
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Article
Microstructure and Optical Functions of Transparent Conductors and their Impact on Collection in Amorphous Silicon Solar Cells
We have developed new procedures for determining the microstructure as well as the index of refraction and extinction coefficient spectra {n(E), k(E)} for textured SnO2 thin films on glass used as the top contact...
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Article
Carrier Transport and Recombination In A-SI:H P-I-N Solar Cells in Dark and Under Illumination
A study has been carried out on the forward bias dark current and the short circuit current -open circuit voltage characteristics of a-Si:H p-i-n solar cells over wide range of illumination intensities. Result...
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Article
Hole Drift-Mobility Measurements in Contemporary Amorphous Silicon
We present hole drift-mobility measurements on hydrogenated amorphous silicon from several laboratories. These temperature-dependent measurements show significant variations of the hole mobility for the differ...
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Article
Protocrystalline Si:H p-type Layers for Maximization of the Open Circuit Voltage in a-Si:H n-i-p Solar Cells
We have revisited the issue of p-layer optimization for amorphous silicon (a-Si:H) solar cells, correlating spectroscopic ellipsometry (SE) measurements of the p-layer in the device configuration with light cu...
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Article
Evolution of Crystallinity in Mixed-Phase (a+μc)-Si:H as Determined by Real Time Spectroscopic Ellipsometry
The ability to characterize the phase of the intrinsic (i) layers incorporated into amorphous silicon [a-Si:H] and microcrystalline silicon [μc-Si:H] thin film solar cells is critically important for cell opti...
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Article
Recombination in n-i-p (Substrate) a-Si:H Solar Cells with Silicon Carbide and Protocrystalline p-Layers
A study was carried out on hydrogenated amorphous silicon (a-Si:H) n-i-p (substrate) solar cell structures with p-a-SiC:H and highly diluted p-Si:H layers grown with different dilution ratios R=[H2]/[SiH4]. The c...
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Article
Light Induced Defect Creation Kinetics in Thin Film Protocrystalline Silicon Materials and Their Solar Cells
Using real time spectroscopic ellipsometry to characterize the microstructure and evolutionary growth of Si:H materials deposited with and without hydrogen dilution, phase diagrams were developed which clearly...
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Article
Characterization of Gap Defect States in Hydrogenated Amorphous Silicon Materials
An enhanced simulation model based on the carrier recombination through these states was developed to characterize the gap defect states in hydrogenated amorphous silicon materials (a-Si:H). The energy depende...
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Article
Transparent Conducting Oxide Sculptured Thin Films for Photovoltaic Applications
Optical losses in thin film solar cells arise due to reflections at the top interfaces where dielectric discontinuities may be significant, e.g., between the glass and transparent conducting oxide (TCO) contac...
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Article
Multichannel Mueller Matrix Analysis of the Evolution of Surface Roughness on Different In-Plane Scales during Polycrystalline Film Processing
Optical analysis of polycrystalline semiconductors and transparent conducting oxides (TCOs) used in thin film photovoltaics is a considerable challenge due to surface roughness and nonuniformities that may exi...
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Article
The Nature of Native and Light Induced Defect States in i-layers of High Quality a-Si:H Solar Cells Derived from Dark Forward-Bias Current-Voltage Characteristics
Results are presented on the defect state distributions in intrinsic a-Si:H layers with and without hydrogen dilution in p-i-n solar cells obtained directly from the analysis of dark forward-bias current-volta...
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Article
The Creation and Annealing Kinetics of Fast Light Induced Defect States created by 1 Sun Illumination in a-Si:H
Preliminary results are presented on the kinetics of fast states at 25°C created by 1 sun illumination in protocrystalline hydrogen diluted a-Si:H films. The results are for the bulk properties of the a-Si:H f...
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Article
Development of Deposition Phase Diagrams for Thin Film Si:H and Si1-xGex:H Using Real Time Spectroscopic Ellipsometry
The growth of hydrogenated silicon (Si:H) and silicon-germanium alloys (Si1-xGex:H) by plasma-enhanced chemical vapor deposition (PECVD) on crystalline silicon (c-Si) substrates has been studied by real time spec...
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Article
Characterization of the Bulk Recombination in Hydrogenated Amorphous Silicon Solar Cells
Dark forward bias current, JD-V, characteristics offer a probe for characterizing carrier recombination and the defect states in the intrinsic layers of hydrogenated amorphous silicon (a-Si:H) solar cells. Detail...
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Article
Evolution of D0 and non-D0 Light Induced Defect States in a-Si:H Materials and Their Respective Contribution to Carrier Recombination
A study has been carried out on the evolution of light induced defects in protocrystalline (diluted) a-Si:H films under 1 sun illumination. A room temperature reversal is observed in the photocurrents at 25 °C...
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Article
Comparison of Phase Diagrams for vhf and rf Plasma-Enhanced Chemical Vapor Deposition of Si:H Films
Deposition phase diagrams are convenient for categorizing the evolution of the surface microstructure and phase with accumulated thickness for hydrogenated silicon (Si:H) films during plasma-enhanced chemical ...
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Article
Contributions of D0 and non-D0 Gap States to the Kinetics of Light Induced Degradation of Amorphous Silicon under 1 sun Illumination
Light induced changes to 1 sun degraded steady state (DSS) have been investigated on hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells and corresponding films fabricated with and without hydrogen dilut...
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Article
Evolution of the Mobility Gap with Thickness in Hydrogen-Diluted Intrinsic Si:H Materials in the Phase Transition Region and Its Effect on p-i-n Solar Cell Characteristics
Insights into the growth processes and evolution of microstructure in intrinsic hydrogenated silicon (Si:H) films obtained from real-time spectroscopic ellipsometry (RTSE) are extended to the characterization ...
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Article
Real Time Optics of Amorphous Silicon Solar Cellfabrication on Textured Tin-Oxide-Coated Glass
A rotating-compensator multichannel ellipsometer has been used to measure the four spectra (1.4-4.0 eV) that describe the Stokes vector of the light beam reflected from the surface of an amorphous silicon (a-S...
