The open circuit voltage of amorphous silicon p-i-n solar cells

Results are presented of an extensive study of V/sub oc/ in a-Si:H p-i-n solar cells deposited by photo-CVD (chemical vapor deposition) and plasma-CVD. The diode parameters under illumination have been analyzed for varying p-layer and carbon graded layer thicknesses and impurity levels. It is found that the diode factor is 1.5 and that the built-in voltage is 1.05 V for most cells, indicating that the diode mechanism does not evolve from diffusion to space-charge recombination. Instead, it is concluded that in typical devices V/sub oc/ is dominated by recombination at the p/i junction. The author reviews previous analyses and conclusions of others and discusses limitations to V/sub oc/.<
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