Valance band offset of TiO2/CuGaO2 hetero-structure measured by x-ray photoelectron spectroscopy

We studied the band offset and alignment of pulsed laser deposited TiO2/CuGaO2 hetero-structure using x-ray photoelectron spectroscopy. Valance band offset (VBO) of TiO2/CuGaO2 interface was calculated using Kraut equation as 2.15 eV, which was in corroboration with VBO obtained directly from valance band onsets. A schematic band alignment diagram for the TiO2/CuGaO2 interface was constructed which showed a type II band alignment with a significant band bending of 0.48 eV. Interface studies of TiO2/CuGaO2 hetero-structure, showing type II band alignment, is important for gaining insight to the design of various photovoltaic devices based on such hetero-structures.