Open-circuit voltage of p-i-n a-Si based solar cells

Experimental studies were conducted to understand the behavior of the open-circuit voltage (V_oc) in a-Si based p-i-n solar cells. J_d-V curves for p-i-n solar cells having various structures were measured and analyzed to understand the transport mechanism of the dark current. It was found that J_d (dark current) was mainly due to the recombination current at the p/i interface region, and V_oc was proportional to the voltage shift of the J_d-V curve to a higher voltage. It was also found that the effective thickness of the interface region was 100 AA and the junction structure of this region was governed by the J_d-V characteristics and V_oc.