Spray pyrolysis deposition and characterization of highly (100) oriented magnesium oxide thin films

Transparent dielectric thin films of MgO has been deposited on quartz substrates at different temperatures between 400 and 600 degrees C by a pneumatic spray pyrolysis technique using Mg(CH3COO)(2).4H(2)O as a single molecular precursor. The thermal behavior of the precursor magnesium acetate is described in the results of thermogravimetry analysis (TGA) and differential thermal analysis (DTA). The prepared films are reproducible, adherent to the substrate, pinhole free and uniform. Amongst the different spray process parameters, the substrate temperature effect has been optimized for obtaining single crystalline and transparent MgO thin films. The films crystallize in a cubic structure and X-ray diffraction measurements have shown that the polycrystalline MgO films prepared at 500 degrees C with (100) and (110) orientations are changed to (100) preferred orientation at 600 degrees C. The MgO phase formation was also confirmed with the recorded Fourier Transform Infrared (FTIR) results. The films deposited at 600 degrees C exhibited highest optical transmittivity (>80%) and the direct band gap energy was found to vary from 4.50 to 5.25 eV with a rise in substrate temperature from 500 to 600 degrees C. The measured sheet resistance and the resistivity of the film prepared at 600 degrees C were respectively 10(13)Omega/square and 2.06x10(7)Omega cm. The surface morphology of the prepared MgO thin films was examined by atomic force microscopy.