Tungsten oxide as a p-type window material in amorphous silicon solar cells

A p-type amorphous tungsten oxide (p-a-WO₃) film was prepared using a vacuum thermal evaporator with a WO₃ source. By replacing a 10 nm-thick p-type amorphous silicon carbide window layer of a pin-type amorphous silicon based solar cell with a 10 nm-thick p-a-WO₃ film, the short circuit current density increased from 12.75 to 13.83 mA/cm². Although the open circuit voltage was limited to 0.65 V due to the smaller work function of the p-a-WO₃, the a-Si based solar cell with the novel p-a-WO₃ window layer has shown a conversion efficiency of 6.05 %. Our research opens a new application field for thin film solar cells.