Effects of gas depletion on dc plasma deposited, a-Si single junction p–i–n solar cells with i-layers deposited at 10 Å/s

The growth rate of a-Si increases with dc plasma current with a single slope at high flow rates but with a reduced slope above a certain power for lower flow rates when using a showerhead type gas delivery system. This is in contrast to saturation of the growth rate under gas depletion conditions previously reported. The change to a smaller slope for lower flow rates at higher powers can be understood in terms of a transition to reactive radical dominated growth. We show that a-Si single junction cell performance deteriorates under gas depletion conditions.