Comprehensive study on Sb-doped zinc oxide films deposited on c-plane Al₂O₃ substrates

Undoped and Sb-doped p-type ZnO films were grown on (001) sapphire using metal organic chemical vapor deposition (MOCVD) technology. The crystal, optical, and electrical properties of the undoped and Sb-doped ZnO film were investigated by X-ray diffraction (XRD), photoluminescence, optical transmittance spectroscopy and Hall measurement system. The XRD patterns indicated both films exhibited preferred orientation along c axis and had a compressive stress. Strong near-band gap emissions of both films were observed in the room temperature photoluminescence spectra. Low temperature photoluminescence spectrum of the ZnO film was dominated by a donor-bound exciton with peak at 3.365 eV. To the Sb-doped ZnO film, donor-bound exciton was buried into the free exciton with peak at 3.371 eV, and emission intensities associated acceptor enhanced. The acceptor binding energy was calculated to be 0.19 eV. The optical bandgap of the Sb-doped ZnO film was estimated to be 3.302 eV. The Sb-doped ZnO film exhibited p-type conductivity with the resistivity of 0.6729 Ω cm, mobility of 6.150 cm² V⁻¹ s⁻¹ and carrier concentration of 1.508 × 10¹⁸ cm⁻³.