Study of Optical Properties of GaMnN

In our previous work, room temperature ferromagnetism of GaMnN thin films with different Mn concentrations were grown on c-sapphire substrates by metal organic chemical vapor deposition (MOCVD). Compared with GaN, the results of optical absorption spectra for the GaMnN samples were shown that a peak of absorption can be observed near 1.44eV, and the absorption coefficient increased with the increase of the Mn content. In this paper, electronic structure and optical properties for several Mn concentrations doping GaN were calculated using density functional theory. The theoretical data were in excellent agreement with the experimental results. Associated with theoretical data, the peak of absorption near 1.44eV is assigned to ⁵T₂→⁵E internal transition between the e state and the t₂ state of Mn³⁺ ion.