Molecular beam epitaxial growth of hexagonal ZnMgO films on Si(1Â 1Â 1) substrates using thin MgO buffer layer

Successful growth of hexagonal ZnMgO films on Si(1 1 1) substrates is demonstrated by using Mg layer followed by MgO growth as a buffer layer. All the layers are grown by MBE using a radio frequency radical cell. The results of the glow discharge optical emission spectroscopy measurement indicate that Zn1−xMgxO films with Mg fraction x up to about 0.5 are obtained without phase separation. Moreover, these ZnMgO films are confirmed to be hexagonal c-oriented through the X-ray diffraction measurement and reflection high-energy electron diffraction observation. The lattice constant and cathodoluminescence peak energy are also investigated as a function of x.