Growth of ZnO thin films on lattice-matched substrates by pulsed-laser deposition

ZnO films were grown on GaN and sapphire substrates by pulse laser deposition, respectively. The effects of crystalline quality on the optical properties in ZnO epitaxial layers were investigated by x-ray rocking curve and photoluminescence. The x-ray rocking curve of the film deposited on the GaN substrate has the full width half maximum (FWHM) of 0.45degrees, whereas the FWHM of the x-ray theta-rocking curve of the ZnO film deposited on a sapphire substrate was measured to be about 0.77degrees. In photoluminescence (PL) measurement, the intensity of UV photoluminescence for the ZnO film on the GaN substrate decreased by approximately two orders of magnitude in comparison with that of the ZnO film on sapphire. It is concluded that the UV luminescence intensity almost does not depend on the textured growth of the ZnO thin film.