Electroabsorption and Transport Measurements and Modeling Research in Amorphous Silicon Based Solar Cells: Phase I Technical Progress Report, March 24, 1998 - March 23, 1999

This report describes work done by the Syracuse University during Phase I of this subcontract. Researchers performed work in the following areas:; 1) In 'electroabsorption measurements and built-in potentials in a-Si:H-based solar cells and devices,' researchers obtained an estimate of Vbi =1.17 V in cells with a-SiGe:H absorber layers from United Solar Systems Corp. 2) In 'solar cell modelingemploying the AMPS computer program,' researchers began operating a simple 'AMPS' modeling site and explored the effect of conduction bandtail width on Voc computed analytical approximations and the AMPS program. The quantitative differences between the two procedures are discussed. 3) In 'drift mobility measurements in a-Si:H made with high hydrogen dilution,' researchers measured electron andhole mobilities in several n/i/Ni (semitransparent) cells from Pennsylvania State University with a-Si absorber layers made under maximal hydrogen dilution and found a modest increase in hole mobility in these materials compared to conventional a-Si:H. 4) In 'electroabsorption spectroscopy in solar cells,' researchers discovered and interpreted an infrared absorption band near 1.0 eV, which theybelieve is caused by dopants and defects at the n/i interface of cells, and which also has interesting implications for the nature of electroabsorption and for the doping mechanism in n-type material.