Effects of nitrogen vacancies induced by Mn doping in (Ga,Mn)N films grown by MOCVD

We have investigated the effects of nitrogen vacancies (VN) induced by Mn doping on the electronic structure and transport properties of (Ga,Mn)N films grown by metal organic chemical vapour deposition (MOCVD). The significant increase in n-type carrier concentration in the (Ga,Mn)N film is attributed to the additional VN induced by Mn doping. Temperature-dependent Hall data indicate that the additional VN is the dominant scattering mechanism in the (Ga,Mn)N film in higher temperature regions. The Mn L2,3 x-ray absorption spectra of the (Ga,Mn)N film shows a multiplet structure, indicating that the Mn ions are present mainly in the Mn2+(d5) states. These can be attributed to the electrons transferring from VN, which is well consistent with the electrical properties. An energy level model involving the charge transfer is proposed to explain the observed electronic structure and transport properties in the system.