Specimens of Mg-doped and In–Mg co-doped p-type GaN epilayer were grown using the metal organic chemical vapour deposition technique. The effect of In co-doping upon the physical properties of p-GaN layer was examined using high-resolution X-ray diffraction, transmission electron microscopy, Hall effect, photoluminescence and persistent photoconductivity at room temperature. An improved crystalline quality and a reduction in threading dislocation density were demonstrated for In doping in p-GaN, according to high-resolution X-ray diffraction and transmission electron microscopic images. The hole conductivity, mobility and carrier density were also significantly improved by In co-doping. Photoluminescence studies of the In–Mg co-doped samples revealed that the peak position was blue shifted to 3.2eV, from the 2.95eV of conventional p-GaN and the photoluminescence intensity was increased by about 25%.

Characteristics of Mg-Doped and In–Mg Co-Doped p-Type GaN Epitaxial Layers Grown by Metal Organic Chemical Vapour Deposition. S.J.Chung, M.S.Kumar, Y.S.Lee, E.K.Suh, M.H.An: Journal of Physics D, 2010, 43[18],185101