Influence of surface optical phonon on the electronic surface states in wurtzite group-III nitride ternary mixed crystals

Abstract:

An intermediate-coupling variational method is presented to investigate the surface electron states in wurtzite AxB1-xN (A, B=Al, Ga and In) ternary mixed crystals (TMCs). Corresponding effective Hamiltonian are derived by considering the surface-optical-phonon (SO-phonon) influence and anisotropic structural effect. The surface-state energies of electron, the coupling constants and the average penetrating depths of the electronic surface-state wave functions have been numerical computed as a function of the composition x and the surface potential V0 for the wurtzite AlxGa1-xN, AlxIn1-xN and InxGa1-xN, respectively. The results show that the surface-state levels of electron are reduced with the increasing of the composition x in wurtzite AxB1-xN. It is also found that the electron-surface-optical-phonon (e-SO-p) coupling lowers the surface-state energies of electron and the shifts of the electronic surface-state energy level in the wurtzite AlxGa1-xN and AlxIn1-xN increase with the increasing of the composition x. However, in the wurtzite InxGa1-xN, the case is contrary. The influence of the e-SO-p interaction on the surface electron states can not be neglected in wurtzite AxB1-xN. This work has been supported by the Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region (No.NJZY16071), the Natural Science Foundation of Inner Mongolia (No.2020MS01008), and the National Natural Science Foundation Project of China (No.11664030). E-mail:[e-mail]