Homoepitaxial growth of high-quality nonpolar ZnO films by MOCVD and evaluation of the homoepitaxial ZnO films by XRD measurement for asymmetric planes



Characteristics of homoepitaxial high-quality nonpolar ZnO (11equation image0) films and a useful measurement method for determining structures of those films are described. Homoepitaxial growth of high-quality nonpolar ZnO (11equation image0) films could be achieved by atmospheric-pressure metal organic chemical vapor deposition using zinc acetylacetonate and oxygen gas. The value of full width at half-maximum (FWHM) of X-ray rocking curves (XRCs) of asymmetrical ZnO (20equation image0) and (11equation image2) planes increased with increase in oxygen gas flow rate, and the change in FWHM value corresponded to FWHM of near-band-edge emission of photoluminescence spectra. On the other hand, the FWHM value of the XRC of the symmetrical ZnO (11equation image0) plane did not change with change in oxygen gas flow rate, and the FWHM values of all samples were nearly equal to the FWHM value of a single crystal ZnO (11equation image0) substrate. The smallest FWHM values of XRCs of ZnO (11equation image0), (20equation image0) and (11equation image2) planes in the sample grown under the condition of an oxygen gas flow rate of 50 sccm were about 30 arcsec, 35 arcsec and 40 arcsec, respectively. These results indicate that the homoepitaxial ZnO (11equation image0) film has good crystallinity. XRC measurement for asymmetrical planes is useful for evaluating homoepitaxial ZnO (11equation image0) films. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)