Comprehensive study of the p-type conductivity formation in radio frequency magnetron sputtered arsenic-doped ZnO film

Arsenic doped ZnO and ZnMgO films were deposited on SiO₂ using radio frequency magnetron sputtering and ZnO–Zn₃As₂ and ZnO–Zn₃As₂–MgO targets, respectively. It was found that thermal activation is required to activate the formation of p-type conductivity. Hall measurements showed that p-type films with a hole concentration of ∼ 10¹⁷ cm⁻³ and mobility of ∼ 8 cm² V⁻¹ s⁻¹ were obtained at substrate temperatures of 400–500 °C. The shallow acceptor formation mechanism was investigated using x-ray photoelectron spectroscopy, positron annihilation, low temperature photoluminescence, and nuclear reaction analysis. The authors suggest that the thermal annealing activates the formation of the As_Zn-2V_Zn shallow acceptor complex and removes the compensating hydrogen center.