Field-effect a-Si:H solar cells with transparent conductive oxide comb-shaped electrodes

We have developed field-effect amorphous silicon solar cells (FESC) with comb-shaped electrodes (CSE) made of transparent conductive oxide (TCO). The FESC is based on the concept of utilizing a special window layer, in which carriers are induced by the field-effect instead of heavy impurity doping, to form a pin (or nip) junction. Pulsed laser deposition was used to fabricate a TCO CSE with a ZnO/ITO/ZnO stacked-layer structure. The FESC exhibited enhanced current output on applying a bias voltage for the field-effect. The conversion efficiency of the field-effect operation was improved by 39% compared with a FESC with a metal CSE. The fill factor was improved markedly by applying a TCO to the CSE.