Realization of p-type ZnO thin films via phosphorus doping and thermal activation of the dopant

TLDR

P2O5 was used to dope ZnO on sapphire, and thermal annealing above 800 °C in N₂ converted the as‑grown n‑type films to p‑type. The resulting p‑type ZnO exhibited hole concentrations of 1.0×10¹⁷–1.7×10¹⁹ cm⁻³, mobilities of 0.53–3.51 cm² V⁻¹ s⁻¹, resistivities of 0.59–4.4 Ω cm, a 3.35 eV photoluminescence peak at 10 K, and demonstrated reproducible, stable performance.

Abstract

A p-type ZnO was prepared on a sapphire substrate using P2O5 as a phosphorus dopant. As-grown n-type ZnO films doped with phosphorus showed electron concentrations of 1016–1017/cm3 and these films were converted to p-type ZnO by a thermal annealing process at a temperature above 800 °C under a N2 ambient. The electrical properties of the p-type ZnO showed a hole concentration of 1.0×1017–1.7×1019/cm3, a mobility of 0.53–3.51 cm2/V s, and a low resistivity of 0.59–4.4 Ω cm. The phosphorus-doped ZnO thin films showed a strong photoluminescence peak at 3.35 eV at 10 K, which is closely related to neutral acceptor bound excitons of the p-type ZnO. This thermal activation process was very reproducible and effective in producing phosphorus-doped p-type ZnO thin films, and the produced p-type ZnO was very stable.