Binding energies of excitons in a strained wurtzite GaN/AlGaN quantum well influenced by screening and hydrostatic pressure

TLDR: In this paper, a variational method combined with a self-consistent procedure is adopted to discuss the binding energies of heavy-hole excitons in a strained wurtzite GaN/Al 0.7N quantum well by considering the hydrostatic pressure effect and screening due to the electron-hole gas.

Abstract: In the framework of effective mass and single-band approximations, a variational method combined with a self-consistent procedure is adopted to discuss the binding energies of heavy-hole excitons in a strained wurtzite GaN/Al0.3Ga0.7N quantum well by considering the hydrostatic pressure effect and screening due to the electron–hole gas. The built-in electric field in such a structure produced by spontaneous polarization and strain-induced piezoelectric polarization is considered in our calculation. A simplified coherent potential approximation is extended to calculate the energy gaps of the ternary mixed crystal AlxGa1−xN. The result indicates that the binding energies of excitons increase nearly linearly with pressure even when taking into consideration the modification of strain. It is also found that the percentage increase of the binding energy with pressure is influenced by the electron–hole density due to the influence of pressure on the screening and exclusion effects. The excitonic binding energies increase obviously with decreasing barrier thickness due to the built-in electric field.