MBE‐grown ZnO film on sapphire substrate with double buffer layers

Abstract

ZnO film was grown on c-Al2O3 substrate by rf-plasma-assisted molecular beam epitaxy. A low temperature (LT) GaN thin layer and a LT-ZnO layer were used as double buffer layers. A high quality ZnO epilayer was obtained by using the double buffer layers. The FWHM values of (002) symmetric and (102) asymmetric ω scans were 90 and 430 arcsec, respectively. Very smooth surface was obtained in step flow growth with rms roughness of 0.9 nm in 10 μm ×10 μm scanned area. The electron mobility of 1 μm thick ZnO epilayer was as high as 152 cm2V−1s−1 with residual carrier concentration of 2.8 × 1016 cm−3. Furthermore, the ZnO film was proved to be Zn polar by coaxial ion collision impact scattering spectroscopy (CAICISS) measurement. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)