A comprehensive study of temperature-dependent reflectance and photoluminescence of Zn(1-x)Mn(x)O thin films grown on c-Al(2)O(3)

Abstract

We present a systematic study of temperature-dependent reflectance (R) and photoluminescence (PL) measurements on ZnMnO films grown by plasma-assisted molecular beam epitaxy. For the first time, the three free-exciton transitions FX(A) (Gamma(7c)-Gamma(u)(7v)), FX(B) (Gamma(7c)-Gamma(9v)), and FX(C) (Gamma(7c)-Gamma(l)(7v)) and the longitudinal-optical phonon replicas of FX(B) and FX(C) of ZnMnO films have been clearly observed in the R spectra. The parameters describing the activation energy and the temperature dependence of the transition energy and broadening have been extracted by fitting the experimental R and PL spectra. The spectral data of ZnMnO films not only show the deterioration of crystalline quality with increasing Mn composition fraction but also indicate the Mn clustering caused by Mn atom segregation.