Effects of oxygen partial pressure on the structural and electrical properties of Al and Sb co-doped p-type ZnO thin films grown by pulsed laser deposition

ZnO:Al_0.01Sb_0.02 thin films were grown on the c-plane sapphire via pulsed laser deposition at 500 °C under different oxygen partial pressures (0.13–66.66 Pa) and their structural and electrical properties were investigated. The thin films deposited under low oxygen partial pressures (0.13–7.99 Pa) grew with a c-axis preferred orientation and a 30° rotated one. At higher oxygen partial pressures (13.33–66.66 Pa), in addition to the main c-axis-oriented domains, partial domains with 32°- and 90°-tilted c-axes were observed. The ZnO:Al_0.01Sb_0.02 thin films deposited at low oxygen partial pressure and high oxygen partial pressure exhibited n-type and p-type conduction, respectively. The X-ray photoelectron spectroscopy analysis exhibited that the thin films contained more Sb⁵⁺ than Sb³⁺; therefore, the p-type conduction was owing to the Sb⁵⁺ ions, which formed the Sb_Zn–2V_Zn complex.