Tungsten oxide as a buffer layer inserted at the SnO2/p-a-SiC interface of <i>pin</i>-type amorphous silicon based solar cells

Abstract

A thermally evaporated p-type amorphous tungsten oxide (p-a-WO3) film was introduced as a buffer layer between SnO2 and p-type amorphous silicon carbide (p-a-SiC) of pin-type amorphous silicon based solar cells. Using the Schottky barrier model, it is shown that the p-a-WO3 layer lowered the Schottky barrier height, which enhanced the open circuit voltage and the blue response compared to a bufferless cell. By inserting a 2-nm-thick p-a-WO3 layer between SnO2 and an 8-nm-thick p-a-SiC layer, the conversion efficiency was increased by 7.3% compared to the optimized bufferless cell only with a 10-nm-thick p-a-SiC window layer.