Band offset and electronic properties at semipolar plane AlN()/diamond heterointerface**Project supported by the Scholarship Council of China (Grant No. 201508340047), the Postdoctoral Science Foundation of China (Grant No. 2016M601993), the Postdoctoral Science Foundation of Anhui Province, China (Grant No. 2017B215), and the Anhui Province University Outstanding Talent Cultivation Program, China (Grant No. gxfxZD2016077).

Abstract

Tailoring the electronic states of the AlN/diamond interface is critical to the development of the next-generation semiconductor devices such as the deep-ultraviolet light-emitting diode, photodetector, and high-power high-frequency field-effect transistor. In this work, we investigate the electronic properties of the semipolar plane AlN()/diamond heterointerfaces by using the first-principles method with regard to different terminated planes of AlN and surface structures of diamond (100) plane. A large number of gap states exist at semi-polar plane AlN()/diamond heterointerface, which results from the N 2p and C 2s2p orbital states. Besides, the charge transfer at the interface strongly depends on the surface termination of diamond, on which hydrogen suppresses the charge exchange at the interface. The band alignments of semi-polar plane AlN()/diamond show a typical electronic character of the type-II staggered band configuration. The hydrogen-termination of diamond markedly increases the band offset with a maximum valence band offset of 2.0 eV and a conduction band offset of 1.3 eV for the semi-polar plane N–AlN()/hydrogenated diamond surface. The unique band alignment of this Type-II staggered system with the higher CBO and VBO of the semi-polar AlN/HC(100) heterostructure provides an avenue to the development of robust high-power high-frequency power devices.