ON THE LACK OF CORRELATION BETWEEN FILM PROPERTIES AND SOLAR-CELL PERFORMANCE OF AMORPHOUS SILICON-GERMANIUM ALLOYS

We have studied the performance of amorphous silicon-germanium alloy single-junction solar cells both before and after light soaking. The intrinsic layers of the cells have different germanium contents. Films were grown on glass with parameters nominally identical to those for the intrinsic layer of the cells and the defect density was measured using the constant photocurrent method. We do not find good correlation between cell performance and the measured defect density for these high quality materials.