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

Abstract

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 <TEX>$800^{\circ}C$</TEX> for 5 minutes in ambient of <TEX>$O_2$</TEX> with pressure of 10Torr. X -ray diffraction shows that the homo-buffer 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 <TEX>$800^{\circ}C$</TEX> possess p-type conductivities. The undoped ZnO film has the highest carrier concentration of <TEX>$1.145{\times}10^{17}cm{-3}$</TEX>. The photoluminescence spectra show the emissions related to FE, DAP and many defects such as <TEX>$V_{Zn}$</TEX>, <TEX>$Zn_O$</TEX>, <TEX>$O_i$</TEX> and <TEX>$O_{Zn}$</TEX>. The p-type defects (<TEX>$O_i$</TEX>, <TEX>$V_{Zn}$</TEX>, and <TEX>$O_{Zn}$</TEX>) are dominant. The undoped ZnO thin film has a better p-type conductivity compared with N-doped ZnO thin film.