Formation of p-type ZnO films with annealing in NH₃ ambient

A p-type ZnO was prepared on a SiO₂/Si (100) substrate by using post-annealing in NH₃ ambient as the nitrogen source. The properties were examined by X-ray diffraction (XRD), Hall-effect measurement, photoluminescence (PL), and secondary ion mass spectrometry (SIMS). ZnO films showed better crystallinity and electron concentration of 10¹⁵ - 10¹⁷ /cm³ with post-annealing in NH₃ ambient. These films were converted to p-type ZnO by an activation thermal annealing process at 800 °C under N₂ ambient. The electrical properties of the p-type ZnO showed a hole concentration of 1.06 × 10¹⁶ /cm³, a mobility of 15.8 cm²/V·s, and a resistivity of 40.18 Ω·cm. The N-doped ZnO films showed a strong photoluminescence peak at 3.306 eV at 13 K, which is closely related to neutral acceptor-bound excitons of the p-type ZnO. In the SIMS spectra, the incorporation of nitrogen was confirmed.