Impact of the vertical strain on the Schottky barrier height for graphene/AlN heterojunction: a study by the first-principles method

Recent years, graphene-based van der Waals (vdW) heterojunction becomes more and more popular in optoelectronics, nanoelectronics, and spintronics device area. Besides, the modulation of Schottky barrier height (SBH) is rather desired to improve the performance of corresponding devices. In the current study, we have focused on the interfacial characteristics and electronic structure of graphene/AlN heterostructure by the first-principles calculations. The results show the intrinsic electronic properties are preserved after graphene and AlN contacting due to the weak interaction between two sublayers. The Bader charge analysis shows that the electrons are transferred from AlN to graphene, leading to graphene as an acceptor while AlN as a donor. Besides, by varying the interlayer distance from 2.5 to 4.3 Å, we found both the n-SBH and p-SBH are significantly tuned. In addition, the optical absorption intensity is enhanced significantly in the graphene/AlN heterojunction. Our findings imply that the SBH is controllable, which is highly desirable in the nano-electronic devices. Graphic abstract