Single-crystalline ZnO films grown on (0001)Al2O3 substrate by electron cyclotron resonance-assisted molecular beam epitaxy technique

High quality epitaxial ZnO films were grown on c-plane sapphire substrates at low temperature using the electron cyclotron resonance-assisted molecular beam epitaxy (ECR-assisted MBE) technique, in which zinc vapor provided by a Knudsen cell reacted with oxygen activated in an ECR source on the surface of sapphire substrate. The crystal structure and the surface morphology of the films we:re investigated. It was confirmed that the ECR-assisted MBE technique was capable of growing high quality epitaxial ZnO films on c-plane sapphire substrates at low temperatures in comparison with CVD or RF sputtering deposition. Furthermore, the FWHM of an X-ray rocking curve of the (0002) peak for a 0.33 mu m-thick ZnO film grown epitaxially at the substrate temperature of 275 degrees C and the oxygen pressure of 2 x 10(-4) Torr was as narrow as 0.58 degrees.