The growth of ZnO on bcc-In2O3 buffer layers and the valence band offset determined by X-ray photoemission spectroscopy

Both In2O3 and ZnO are potential oxide semiconductor materials for optoelectronics devices. Semi-polar (101) plane wurtzite (w-)ZnO films were grown on bcc-In2O3(111) by metal organic chemical vapor deposition and the epitaxial relation is w-ZnO(101) parallel to bcc-In2O3(111). We have measured the valence band offset (VBO) of w-ZnO(101)/bcc-In2O3(111) heterojunction to settle the question of the band line-up of the ZnO/In2O3 heterojunction. Our result shows that the valence band maximum (VBM) of ZnO(101) lies similar to 0.49 eV below the VBM of bcc-In2O3(111), and the conduction band maximum (CBM) of w-ZnO(101) is about 0.05 eV lower than the CBM of bcc-In2O3 (111), which shows that their CBMs are nearly at the same level.