Band offset studies in pulse laser deposited Zn1−xCdxO/ZnO hetero-junctions

The valence and conduction band offsets of Zn1−xCdxO/ZnO hetero-junctions deposited by pulsed laser deposition technique were estimated by X-ray photoelectron, valence band, and UV-visible spectroscopy. Type-II band alignment (staggered gap) with ratios of conduction band to valence band offsets (ΔEC/ΔEV) was found to be 0.77 and 0.59 for Zn0.95Cd0.05O/ZnO and Zn0.90Cd0.10O/ZnO hetero-structures, respectively, which can be used in longer wavelength regime optoelectronic devices. The higher value of valence band offset as compared to conduction band offset suggests that the transport at interface is mainly due to electrons.