Effect of vanadium oxide interfacial layer for electrical contact on p-type silicon

Abstract

Vanadium oxide interfacial layer between p-type silicon and indium tin oxide was studied as a hole transfer layer in solar cell application. The vanadium oxides deposited by sputtering technique with various conditions were investigated in terms of gap states using spectroscopic ellipsometry. As the Ar gas flow rate increases from 10 sccm to 40 sccm, the gap state of vanadium oxide thin films was reduced, and then it results in decrease of current due to reduction of carriers from p-type semiconductor to electrode for the solar cell applications. In the vanadium oxide films deposited by oxygen gases as reactive gas, a strong confinement of gap state near 1.7 eV as a transition energy appears, and this results in decreasing of total amount of density of states of interfacial layer. In the silicon solar cells with the vanadium oxide thin films deposited at 30 sccm Ar gas flow rate as an interfacial layer between indium tin oxide and p-type Si, it appears that the photoelectric conversion efficiency increases up to about 10% more than that of solar cell without interfacial layer.