Fabrication of p-Type ZnO:N Films by Oxidizing Zn3N2 Films in Oxygen Plasma at Low Temperature

Abstract

The oxygen vacancy (VO) is known as the main compensation center in p-type ZnO, which leads to the difficulty of fabricating high-quality p-type ZnO. To reduce the oxygen vacancies, we oxidized Zn3N2 films in oxygen plasma and successfully prepared p-type ZnO:N films at temperatures ranging from room temperature to 300 °C. The films were characterized by X-ray diffraction (XRD), non-Rutherford backscattering (non-RBS) spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectrum, and Hall Effect. The results show that the nitrogen atoms successfully substitute the oxygen sites in the ZnO:N films. The film prepared at room temperature exhibits the highest hole concentration of 6.22 × 1018 cm−3, and the lowest resistivity of 39.47 Ω∙cm. In all ZnO:N films, the VO defects are reduced significantly. At 200 °C, the film holds the lowest value of VO defects and the strongest UV emission. These results imply that oxygen plasma is very efficient in reducing VO defects in p-type ZnO:N films, and could greatly reduce the reaction temperature. This method is significant for the development of ZnO-based optoelectronic devices.

Keywords

• p-type ZnO:N films
• oxygen vacancy (VO)
• zinc nitrite (Zn3N2)
• oxygen plasma