SINGLE-CRYSTALLINE SILICON SOLAR-CELLS WI TH HIGH-EFFICIENCY OF 23.5-PERCENT

High-efficiency single crystalline silicon solar cells were technicall y developed as an indispensable element to develop a high-efficiency p hotovoltaic system in the future. Two technical elements to raise the efficiency of the cells were adopted: Backside partial heterojunction fabricated through the deposition of a mu c-Si:H film on a thermal oxi de with partially etched micro-windows; low-temperature diffusion of p hosphorus in fabricating an n(+)p junction. These elements were reveal ed to improve the collection of minority carriers at the back side and the front side, respectively. Through these developments, a high effi ciency of 23.5% was obtained for a 5 X 5 cm(2) cell.