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

作者：李根小; 闫祖威^*

来源：Optoelectronics Letters, 2021, 17(01): 22-28.

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.