Photoluminescence and structure properties ofZn1−xMgxO films grown by RF magnetron sputtering

Abstract

A number of Zn1−xMgxO (x = 0–0.16) films on Si(100) substrates were prepared by RF magnetron sputtering andannealed at different temperatures. X-ray diffraction (XRD) and atomic forcemicroscopy (AFM) spectra indicate that the crystal structure of the films forx>0 is the same as that of the hexagonal microcrystal ZnO. UV emission peaksfor free excitons (and assisted phonon replicas) and electron–hole plasma(E–H) are found in the photoluminescence from the films, where the E–H has asuperlinear five-times-enhanced lasing effect. The blue shift of the UV peaks in thephotoluminescence spectra is found to be associated with increasing Mg content in theZn1−xMgxO films, and the peak intensity is also reinforced significantly as the annealing temperature isincreased. The green emission due to the oxygen vacancy was very weak, indicating that a goodstoichiometry was maintained in the films. The minimum lasing threshold of the samples is35 kW cm−2, correspondingto ∼100 nm hexagonal microstructure.