Effect of absorbed water on an indium oxide insulator (BeO⋅SiO2)-p-silicon solar cell

An In2O3/p-Si heterojunction solar cell with an interfacial oxide of beryllium and silicon was investigated. It was found that an efficiency of the heterojunction solar cell was rather low initially but was increased gradually up to 10% after the cell was exposed to an ambient containing water vapor. The effect was qualitatively explained in terms of a trap-assisted tunneling model: Hydroxyl groups absorbed in the interfacial composite oxide layer introduce traps into the oxide band gap which assist selective tunneling of electrons.