Mechanism of doping of Mg in GaN thin film grown on c-plane sapphire substrate by plasma assisted-metalorganic chemical vapor deposition (PA-MOCVD) method have been investigated. The growth was carried out at temperature of 680 DC, which flow rate of Cp2Mg as dopant source was varied of 0.003; 0.006; 0.009 and 0.012 sccm The Van der Pauw technique, X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize their electric, crystallographic and morphology properties. Hole concentrations of up to 1019 cm-3 have been observed for Mg-doped GaN films without any post-growth annealing. The XRD analysis showed change of the FWHMs for the (0002) orientation plane from Mg-doped GaN films. The difference of the atomic radius between Ga and Mg atoms causes lattice distortion in crystal. This lattice distortion generates dislocation and causes growth of the layer to be three-dimensional as showed on SEM images. Keywords: Mg-doped GaN, PA-MOCVD, Van der pauw technique, XRD, SEM. A. Subagio1,2, H. Sutanto1,2, E. Supriyanto1,3, M. Budiman1,P. Arifin1, Sukimo\ M. Barmawi1 1Laboratory for Electronic Material Physics, Dept. of Physics, ITB, Bandung 40132, Indonesia 2Dept. of Physics, Diponegoro University, Semarang, Indonesia 3Dept. of Physics, Jember University, Jember, Indonesia
