Influence of molar ratio of Sb/Zn on the crystal, electrical and optical properties of Sb-doped ZnO films

Sb-doped p-type ZnO films were grown on sapphire substrate by metal organic chemical vapor deposition method. The influence of the molar ratio of Sb/Zn on the crystal, electrical and optical properties of the Sb-doped ZnO films was investigated by X-ray diffraction (XRD), Hall measurement system, optical absorption and photoluminescence spectroscopy. XRD patterns revealed all Sb-doped ZnO films were polycrystalline structures with strong c-axis orientation preferred. Electrical measurement results indicated Sb-doped ZnO films exhibited p-type electrical properties, and carrier concentrations were in the range of 10−17-10−18 cm−3. Low temperature photoluminescence measurement confirmed the existence of Sb in Sb-doped ZnO film. The photoluminescence spectrum of the Sb-doped ZnO film revealed the transition between the free electrons and acceptors peak at 3.243 eV, the acceptor-bound exciton peak at 3.319 eV and the donor-acceptor pair exciton at 3.200 eV. The thermal binding energy of the Sb accepter was estimated to be 0.19 eV.