Multi-trench-based technique to improve amorphous SiGe thin-film solar cell performance
In order to improve the electrical performance of the conventional amorphous SiGe thin-film solar cells, a new multi-trench technique has been proposed. In this method, the multi-trench is created in the intrinsic SiGe layer and filled with p-type doped Si. The p-type trenches in the intrinsic SiGe layer improve the electrical performance of the proposed design. Electrical characteristics of the proposed structure are analyzed and optimized by 2-D numerical modeling and compared with conventional amorphous SiGe thin-film solar cell characteristics. The extracted results show that the multi-trench-based technique has excellent effect on the fill factor and efficiency of the device.
Amorphous silicon based photovoltaics—from earth to the “final frontier”
We highlight the advances made in amorphous silicon alloy photovoltaic technology leading to large-scale commercial deployment. The paper discusses multijunction devices made on lightweight flexible substrates; various aspects of attaining high efficiency devices are described. The eminent role of the roll-to-roll continuous deposition technique in propelling the technology to global market is elucidated. The logical emergence of this technology as a lightweight solar-power generator for extraterrestrial application is discussed. Results of high specific power under space conditions are presented. The future of the technology in terms of both device efficiency and product efficacy are given.
High quality, relaxed SiGe epitaxial layers for solar cell application
Abstract Epitaxially grown, relaxed Si 1− x Ge x layers with x≤0.1 were grown on a Si (100) substrate by means of reduced pressure chemical vapor deposition at a temperature of 750 or 800°C. The analysis carried out on the grown layers revealed a very high material quality indicated by the low density of dislocations (10 5 cm −2 ) and the high diffusion length which was deduced from the measurements of electron beam induced current (EBIC) performed on the as-grown layers. Transmission electron microscopy (TEM) measurements showed that the threading dislocation segments do not extend inside the layer but are rather confined to the Si/SiGe interface, which results in a low density of dislocations in the material. The processed solar cells made from these SiGe layers showed a higher infrared response than those made of a corresponding Si grown and processed under similar conditions. No degradation of the solar cell performance caused by the dislocations in the SiGe layers has been observed.