Effect of oxygen partial pressure ratios on the properties of Al-N co-doped ZnO thin films

p-Type zinc oxide (ZnO) thin films with C-axis orientations were realized using the DC reactive magnetron sputtering by Al and N co-doping method. Second ion mass spectroscopy (SIMS) tests proved that both Al and N were doped in the ZnO films and the incorporation of Al facilitated the N solution into ZnO, thus promoted the formation of p-type conduction. When oxygen partial pressure ratios was 40% or 85%, the as-grown ZnO thin films showed p-type conduction, and the latter had better electrical properties. The obtained p-type ZnO films showed a resistivity of 157 Ω cm, a hole concentration of 5.59×1017 cm−3, and a Hall mobility of 0.0711 cm2/V s at room temperature. X-ray diffraction (XRD) patterns showed that the ZnO film prepared in 60% of oxygen partial pressure ratio had the best C-axis orientation. The as-grown ZnO films possessed transmittance of about 90% in the visible region.