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Characteristics of Mg-doped and In–Mg co-doped p-type GaN epitaxial layers grown by metal organic chemical vapour deposition

2010; Institute of Physics; Volume: 43; Issue: 18 Linguagem: Inglês

10.1088/0022-3727/43/18/185101

1361-6463

S. J. Chung, Manohar Kumar, Y. S. Lee, Eun‐Kyung Suh, M. An,

Ga2O3 and related materials

Mg-doped and In–Mg co-doped p-type GaN epilayers were grown using the metal organic chemical vapour deposition technique. The effect of In co-doping on the physical properties of p-GaN layer was examined by high resolution x-ray diffraction (HRXRD), transmission electron microscopy (TEM), Hall effect, photoluminescence (PL) and persistent photoconductivity (PPC) at room temperature. An improved crystalline quality and a reduction in threading dislocation density are evidenced upon In doping in p-GaN from HRXRD and TEM images. Hole conductivity, mobility and carrier density also significantly improved by In co-doping. PL studies of the In–Mg co-doped sample revealed that the peak position is blue shifted to 3.2 eV from 2.95 eV of conventional p-GaN and the PL intensity is increased by about 25%. In addition, In co-doping significantly reduced the PPC effect in p-type GaN layers. The improved electrical and optical properties are believed to be associated with the active participation of isolated Mg impurities.