Investigation of optical and electrical properties of Mg-doped p-InxGa1-xN, p-GaN and p-AlyGa1-yN grown by MOCVD

Mg-doped p-InxGa1-xN (0x0.045) and p-AlyGa1-yN (0y0.095) layers were grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD). We investigated the activation energy of Mg dopant in Mg-doped p-InGaN, p-GaN and p-AlGaN, as confirmed by PL emission lines of the band to impurity transition of free electrons with neutral Mg acceptors. Under the same Mg doping concentration of 2X1019cm-3, the band to acceptor emission energy E(e-, A0) of Mg-doped p-type InxGa1-xN decreased with increasing the In composition, whereas the E(e-, A0) of Mg-doped p-type AlyGa1-yN increased with Al composition. It suggests that the activation energy of Mg dopant has proportional relationship with the band gap energy of III-nitrides. The Hall measurements showed that the hole concentration of Mg-doped p-type In0.045Ga0.955N was 1.3X1018cm-3 and that of Mg-doped p-type Al0.075Ga0.925N was 8.9X1016cm-3. Keyword: A1. Doping; A3. Metalorganic chemical vapor deposition; B1. Nitrides PACS: 78.55.C; 73.50.J; 71.55; 68.55.L