Measurement of polar C-plane and nonpolar A-plane InN/ZnO heterojunctions band offsets by x-ray photoelectron spectroscopy

The valence band offsets of the wurtzite polar C-plane and nonpolar A-plane InN/ZnO heterojunctions are directly determined by x-ray photoelectron spectroscopy to be 1.76 +/- 0.2 eV and 2.20 +/- 0.2 eV. The heterojunctions form in the type-I straddling configuration with a conduction band offsets of 0.84 +/- 0.2 eV and 0.40 +/- 0.2 eV. The difference of valence band offsets of them mainly attributes to the spontaneous polarization effect. Our results show important face dependence for InN/ZnO heterojunctions, and the valence band offset of A-plane heterojunction is more close to the "intrinsic" valence band offset.

863 High Technology R&D Program of China 2007AA03Z402 2007AA03Z451 Major State Basic Research Project of China 2006CB604907 National Science Foundation of China 60506002 60776015The authors are grateful to Professor Huanhua Wang and Dr. Tieying Yang of the Institute of High Energy Physics, Chinese Academy of Science. This work was supported by the 863 High Technology R&D Program of China (Grant Nos. 2007AA03Z402 and 2007AA03Z451) ,the Special Funds for Major State Basic Research Project of China (973 program) (Grant No. 2006CB604907), and the National Science Foundation of China (Grant Nos. 60506002 and 60776015).