LIQUID-TARGET PULSED-LASER DEPOSITION OF GALLIUM NITRIDE THIN-FILMS

We have prepared gallium nitride (GaN) thin films using our newly deve loped liquid-target pulsed laser deposition (LTPLD) system using Ga an d ammonia (NH3) as the reactants at a deposition temperature as low as 600 degrees C. We have shown that single c-axis oriented GaN films co uld be formed on various substrates (even on a fused silica) if a thin zinc oxide layer was first grown on the substrate. The obtained sampl es show a smooth surface morphology and high optical transparency in t he visible spectral region. The bandgap of these GaN samples obtained from their absorption spectra is about 3.45 eV. A band-band transition photoluminescence peak is located at around 368 nm wavelength. Furthe rmore, the experiment demonstrates the advantages of the LTPLD in the prevention of particulates on the growing films over the solid-target PLD. (C) 1998 Elsevier Science B.V.