Influence of Sb doping on the structural, optical and electrical properties of p-ZnO thin films prepared on n-GaN/Al2O3 substrates by a simple CVD method

ZnO thin films with different Sb doping concentrations were prepared on n-GaN/Al2O3 substrates by simple chemical vapor deposition. Field-emission scanning electron microscopy (FE-SEM) showed that the morphologies of ZnO thin films were rougher and the size of the crystal grains reduced with increasing Sb concentration. The X-ray diffraction measurements indicated that the (002) diffraction peak positions of samples shifted gradually towards the lower angle side, which explained the substitution of Sb3+ into the Zn site by Sb doping. In addition, Hall measurement results indicated that Sb doped ZnO thin films had p-type conductivity, and the optimal Sb2O3/ZnO mass ratio for p-type ZnO thin film was approximately 1:4. Optical absorption spectrum measurement indicated that the energy gaps of the samples were evidently narrowed with increasing Sb doping concentration.