Synthesis and properties of p-type nitrogen-doped ZnO thin films by pulsed laser ablation of a Zn-rich Zn₃N₂ target

Epitaxial ZnO thin films doped uniformly with nitrogen at 10²⁰ atoms/cm³ were fabricated by pulsed laser ablation of a Zn-rich Zn₃N₂ target. The films grown at 300 °C and annealed at 600 °C in O₂ showed p-type conductivity. Two acceptor levels at 105 and 224 meV were determined by temperature-dependent Hall and photoluminescence measurements of the p-type samples. Transmission electron microscopy studies revealed that the p-type ZnO films consist of 10–20 nm columnar grains with a high density of defects and grain boundaries that may facilitate the annihilation of native donors and the activation of acceptors during postdeposition annealing.