Hydrogen ion motion in amorphous silicon solar cells at elevated temperatures

Electric field-enhanced degradation has been observed in amorphous silicon solar cells exposed to intense illumination (45-60 suns) at elevated temperatures (>160 degrees C). The front tin oxide contacts of both p-i-n and n-i-p cells darken significantly when a strong reverse bias is applied at elevated temperatures and under intense illumination. Compositional profiles of the cells show that a strong reverse bias causes a depletion of hydrogen near the contacts. These results are interpreted in terms of proton motion near the p/i interface of p-i-n cells and negative hydrogen ion motion near the i/n interface. (C) 1996 American Institute of Physics.