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Amorphous AsxS100−x films were prepared by thermal evaporation and plasma-enhanced chemical vapour deposition (PECVD). Reversible photodarkening upon illumination with white light at 300 and 77 K was studied for both types of films. The magnitude of photodarkening increased with increasing As content, being somewhat larger for the evaporated films than for the PECVD ones. In agreement with our previous observations in the amorphous As–Se and Ge–Se systems, the shift of the optical absorption edge was not parallel but was always accompanied by a decrease in the slope of the Tauc curve, indicating an increase in disorder. The kinetics of the photoinduced optical shift could be best described by a stretched exponential law. This can be explained within Tanaka''s “single–double well model” with the addition that the process is most probably a kind of self-limiting process, whereby excitation to a quasi-stable state (photodarkening) and annealing (thermal and photoinduced) are simultaneously operative. [Copyright &y& Elsevier]

Focuses on a study which determined the properties of doped and undoped amorphous silicon films deposited by the homogenous chemical vapor deposition (HOMOCVD) technique. Information on HOMOCVD; Methodology of the study; Results and discussion.

Presents a study that examined the fabrication of conventional and electromagnetically casted multicrystalline silicon solar cells using different passivation schemes. Implementation of plasma-enhanced chemical-vapor-deposition; Information on multicrystalline silicon; Discussion on hydrogen plasma passivation.

We have investigated fine grained polycrystalline silicon thin films grown by direct chemical vapor deposition on oxidized silicon substrates. More specifically, we analyze the influence of the doping type on the properties of this model polycrystalline silicon material. This includes an investigation of defect passivation and benchmarking of minority carrier properties. In our investigation, we use a variety of characterization techniques to probe the properties of the investigated polycrystalline silicon thin films, including Fourier Transform Photoelectron Spectroscopy, Electron Spin Resonance, Conductivity Activation, and Suns-Voc measurements. Amphoteric silicon dangling bond defects are identified as the most prominent defect type present in these layers. They are the primary recombination center in the relatively lowly doped polysilicon thin films at the heart of the current investigation. In contrast with the case of solar cells based on Czochralski silicon or multicrystalline silicon wafers, we conclude that no benefit is found to be associated with the use of n-type dopants over p-type dopants in the active absorber of the investigated polycrystalline silicon thin-film solar cells. [ABSTRACT FROM AUTHOR]

Thin film monocrystalline silicon solar cells based on porous silicon (PS) layer transfer processes could be cost-effective because of their lower consumption of material use and the potential for high efficiency. The process is based on our ability to separate thin porous films (p+) of desired thickness and area from Si substrate. Crystallinity of these porous films is studied with XRD for their suitability for Si epitaxy. AFM is employed to study the Si substrate surface roughness after one or more porous film separations. The roughness stabilizes after four film separations. Annealing of the porous films at temperatures above 1050 °C results in a closed surface, suitable for Si epitaxy. XRD analysis of epitaxially deposited Si layer on annealed PS film revealed its high mono-crystalline quality. A FMS solar cell of 12% efficiency has been realized in an 18 μm thin epitaxial layer. [Copyright &y& Elsevier]