Time-dependent density functional theory study on optical properties of GaN doped with alkaline-earth atom

Abstract

The absorption and the emission spectra of GaN and (Ga,AE)N (AE = Be, Mg, Ca) were calculated by using TDDFT method with cluster model. The calculation results show that Ga 26N 26H 50 cluster only has very weak absorption but has some emission bands in visible region. The band-to-band emission appears around 3.56 eV. If alkaline-earth atoms (Be, Mg and Ca) are doped into GaN, the blue emission band around 3.0 eV appears. Thereinto, Ga 25Ca 1N 26H 50 cluster shows a weaker yellow emission band and a stronger blue one (2.92 eV), which make (Ga,Ca)N material a promising candidate to emit blue light.