Effect of lattice structure changes caused by Al component on optical properties of AlGaN materials

Compared with other emitter devices, the light emitting efficiency of emitter based on AlGaN material is very low, and with the further research, the unique optical polarization characteristic of AlGaN material is considered as the main reason of its low light emission efficiency. In this paper, the effect of lattice structure changes caused by Al component on the optical properties of AlGaN materials is studied by using the first principles. The results show that the changes in lattice structure cause the ratio of the CH subband luminescence in the high Al component is greater which is not favored for light emission. The reflectivity, refractive index and absorption coefficient of 200-400 nm wavelength ultraviolet light are relatively weaker in high Al components which means lattice change is beneficial to the improvement of light extraction efficiency.