Electronic structure and the optical properties of GaN (0001) surface from first-principles study

Abstract

The geometrical structure of GaN (0001) surfaces supercell of GaN was optimized by using the ultra-soft pseudopotential method of total-energy plane wave based on the density functional theory (DFT) .Electronic structure, Density of states , band structure and optical properties were calculated and discussed in detail.Geometry optimization indicates that largest atomic relaxation occurs to metal atoms(Ga) in surface layers where all atoms are displaced inward,and the interlayer distances vary large, total polarization strength is strong. The band gap of GaN (0001) surface is obviously narrower than that of GaN, the luminescence spectra shift red.The two aspects go against making high efficiency white-light LED.This paper provides theoretical foundation of GaN (0001) surface and the direction fo making high efficiency white-light LED form first-principles calculation.