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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
Temperature Dependence of a Hydrogen Doublet Site in Light-Soaked a-Si:H From 1H NMR
We investigate the temperature dependence of an additional 1H NMR signal that appears in aSi:H at T = 7 K only after light soaking. This “doublet” signal is attributed to a pair of hydrogen atoms approximately 2....
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Article
1H NMR Evidence for a Change in the Local Hydrogen Environment of Sites Associated with the Staebler-Wronski Effect in a-Si:H
We study the H NMR line shapes of a sample of a-Si:H under several conditions: 1) as grown, 2) light-soaked for 600 hours, and 3) light-soaked followed by annealing at different temperatures. At T = 7 K, the NMR ...
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Article
Effect of Temperature and Temperature Uniformity on Plasma and Device Stability
We have investigated the changes in the cathode potential in a dc discharge of silane and hydrogen used to deposit the intrinsic layer of p-i-n type solar cells at deposition rates from 1 to 10Å/s with the sup...
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Article
Infrared Charge-Modulation Spectroscopy of Defects in Phosphorus Doped Amorphous Silicon
We present infrared charge-modulation absorption spectra on phosphorus-doped amorphous silicon (a-Si:H:P) with do** levels between 0.17%–5%. At higher do** levels (1%–5%) we find a sharp spectral line near...
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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
Room Temperature Recovery of Light Induced Changes in Amorphous Silicon Solar Cells
We have observed the recovery of the performance of amorphous silicon (a-Si:H) based solar cell (especially the fill factor) at temperatures between 25°C and 170°C after ∼600 hours of light soaking under 1 sun...
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Article
The Concentration of (SiH2)n Sites in Low and High Defect Density a-Si:H
The concentration of polysilane chains (SiH2)n, where n ≥ 1, is estimated for higher quality hydrogenated amorphous silicon (a-Si:H) by pulsed proton nuclear magnetic resonance techniques (1H NMR). Our measuremen...
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Article
Absence of a Steady State in Hydrogen Diluted Silane Plasmas Due to Mass Dependent Gas Pum** Speeds and Its Consequences
We have investigated the cause for continued changes in the silane related species observed using mass spectroscopy during i-layer deposition process lasting several tens of minutes. Silane decomposition is fo...
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Article
Semiconductor laser crystallization of a-Si:H on conducting tin-oxide-coated glass for solar cell and display applications
Semiconductor laser (λ=805 nm) crystallization of hydrogenated amorphous silicon (a-Si:H) deposited on a low-cost fluoride-doped tin-oxide-coated glass substrate is demonstrated. X-ray diffraction confirms tha...
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Article
Observation of a Hydrogen Doublet Site in High Defect Density As-Grown a-Si:H by 1H NMR
1H NMR studies of hydrogenated amorphous silicon (a-Si:H) with ~1017 cm−3 defects grown by PECVD with a rate of 5 A/s show the existence of a hydrogen doublet for both as-grown and light-soaked samples. We observ...
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Article
Surgical management of native valve endocarditis
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Article
Technology transfer challenges in the manufacturing of a-Si tandem solar cells
BP Solar started commercial production of amorphous silicon tandem solar cells in Toano, Virginia in 1997. The scale-up process has involved overcoming technology challenges in several areas. It was necessary ...
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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
Effects of low-temperature annealing on the initial and stabilized performance of amorphous silicon solar cells
We have recently observed that the initial performance of amorphous silicon (a-Si) solar cells can be improved by up to several % by annealing the cells at successively lower temperatures for successively long...
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Article
A Comparison of the Degradation and Annealing Kinetics in Amorphous Silicon and Amorphous Silicon-Germaniumsolar Cells
The degradation and annealing kinetics of both a-Si:H and a-SiGe:H single-junction solar cells were investigated under varying conditions. In every case, the kinetics associated with degradation and annealing ...
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Article
Performance of a-Si-H Solar Cells at Higher Growth Rates
We have studied the effects of external growth parameters during the deposition of the i-layers of a-Si p-i-n solar cells using dc plasma decomposition of silane-hydrogen mixtures at growth rates of up to 3A/s...
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Article
In-Situ Monitoring of Surface Hydrogen on the a-SiGe:H Films
The bonded hydrogen on the growing surface of hydrogenated amorphous silicon germanium (a-SiGe:H) alloy films has been investigated by use of infrared reflection absorption spectroscopy (IR-RAS). When the allo...
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Article
Modified Triode Plasma Configuration Allowing Precise Control of Ion-Energy for Preparing High Mobility a-Si:H
We have previously shown that the carrier drift mobility in amorphous silicon can be enhanced by optimizing the ion-bombardment energy during growth on conducting substrates. However, there exists a lack of re...
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Article
Dependence of Field-Effect Mobility on Deposition Conditions in a-Si:H TFT
High electron Mobility (over 3 cm2/Vs) thin film transistors (TFTs) have been fabricated using a-Si:H on thermally oxidized crystalline Si substrate. The procedures for fabricating the high performance TFTs are p...
