Analysis of Photoluminescence for N-doped and undoped p-type ZnO Thin Films Fabricated by RF Magnetron Sputtering Method

N-doped ZnO thin films were deposited on n-type Si(100) and homo-buffer layer, and undoped ZnO thin film was also deposited on homo-buffer layer by RF magnetron sputtering method. After deposition, all films were in-situ annealed at 800 C for 5 minutes in ambient of O2 with pressure of 10 Torr. X-ray diffraction shows that the homobuffer layer is beneficial to the crystalline of N-doped ZnO thin films and all films have preferable c-axis orientation. Atomic force microscopy shows that undoped ZnO thin film grown on homo-buffer layer has an evident improvement of smoothness compared with N-dope ZnO thin films. Hall-effect measurements show that all ZnO films annealed at 800 C possess p-type conductivities. The undoped ZnO film has the highest carrier concentration of 1.145x10 cm. The photoluminescence spectra show the emissions related to FE, DAP and many defects such as VZn, ZnO, Oi and OZn. The p-type defects (Oi, VZn, and OZn) are dominant. The undoped ZnO thin film has a better p-type conductivity compared with N-doped ZnO thin film.