Structural Characterization and Photoluminescent Properties of Zn 1- x Mg x O Films on Silicon

Zn 1- x Mg x O films have been grown on silicon at various substrate temperatures by pulsed laser deposition. The structural and photoluminescent properties of films as a function of substrate temperature have been studied. The optimized substrate temperature is 650°C. The x-ray diffraction spectra indicate that the films are highly C -axis oriented, and no phase separation is observed. The crystal grain size of the films is about 100 nm as examined by atomic force microscopy. The cross-sectional transmission electron microscopy verified the C -axis orientation of the Zn 1- x Mg x O. These films showed ultraviolet photoluminescence at room temperature. The near-band-edge emission peak of the Zn 1- x Mg x O film deposited at 600°C has a blueshift (0.40 eV) larger than that of the film deposited at 500°C (0.33 eV). The ratio of the near-band-edge to defect level peak intensity is as large as 159.