Achieve p-type conduction in N-doped and (Al,N)-codoped ZnO thin films by oxidative annealing zinc nitride precursors

N-doped and (Al,N)-codoped ZnO films were synthesized by oxidative annealing of (Zn + Zn₃N₂) films, which were fabricated by reactive magnetron sputtering. Both n- and p-type conductions were obtained in these ZnO:N and ZnO:AlN films. Optimal oxidation treatments for achieving p-type ZnO are annealing at 400–600 °C for 10–60 min, depending on the film thickness and morphology. The electric properties were found to be very sensitive to the annealing conditions and film structure. As-deposited (Zn + Zn₃N₂) films with and without Al addition had carrier concentrations of 10²¹–10²² cm⁻³. After conversion to ZnO, the n-type films had a carrier concentrations up to 10¹⁹ cm⁻³, whereas the p-type ZnO:N films had hole concentrations of 10¹⁴–10¹⁶ cm⁻³. (Al,N)-codoping increased the hole concentration of p-type film to 10¹⁸ cm⁻³ despite a decrease in Hall mobility. The photoluminescence properties of the p-type ZnO films were also investigated. The synthesis of p-type ZnO:AlN by oxidative annealing is believed to provide an alternative approach to realize p-type conduction in codoped ZnO film by using N₂ as the N source.