Band offset measurements in Zn_1−xSb_xO/ZnO hetero-junctions

Accurate knowledge of the alignment of conduction and valence bands of layers at the heterojunction and warrant knowledge of the band offsets at the interface is essential for Zn_1−xSb_xO/ZnO based quantum well device designing and modeling. Under this scenario, valence band offsets of Zn_1−xSb_xO/ZnO heterostructures grown by the pulsed laser deposition technique was measured by photoelectron spectroscopy and consequently, the conduction band offset was calculated by UV-visible spectroscopy. The change in band alignment has been observed with the dopant (Sb) concentration. Ratios of conduction band offset to valence band offset were estimated to be 1.67 and 0.04 for x = 0.03 and 0.06, respectively, for Sb doped films. A Type-II band alignment was observed at the Zn_0.97Sb_0.03O/ZnO interface, whereas the Type-I band alignment took place at the Zn_0.94Sb_0.06O/ZnO interface. (paper)