Ternary Zn1-xMgxO (0 < x < 0.42) alloy thin films with complete c-axis orientation have been deposited on p-type Si(100) substrate by pulsed laser deposition. X-Ray diffraction measurements indicate that the hexagonal wurtzite type structure of Zn1-xMgxO can be stabilized up to Mg content x similar to 0.37. The deposition temperature was found to exert evident influence on the crystalline grain size and c-axis orientation of the film. Zr0.8Mg0.2O film grown at 650 degreesC displays the narrowest full width of half maximum value of similar to0.19degrees for (002) reflection peak and the largest grain size (similar to150 nm in diameter). An apparent blueshift (similar to40 nm similar to0.40 eV) in near band edge (NBE) emission peak has been observed in the room temperature photoluminescence (PL) spectra of Zn0.8Mg0.2O compared with that of ZnO. The ratio (R=I-NBE/I-DL) of NBE intensity to defect level (DL) peak intensity was found to be as large as 159, indicating that the film is of high crystalline quality and is nearly defect free. High resolution transmission electron microscopy photograph indicates that the c-axis oriented Zn0.8Mg0.2O film was grown on an amorphous SiO2 intermediate layer with similar to8 nm thickness. (C) 2003 Elsevier B.V. All rights reserved.