Molecular beam epitaxy of rare-earth trifluoride, RF3 (R=Ce, Nd, Er, Lu) layers

Abstract RF3 (R=Ce, Nd) layers of hexagonal structure and RF3 (R=Er, Lu) layers of orthorhombic structure were grown on Si(1 1 1) substrates at 700 °C by molecular beam epitaxy (MBE). Their surface characteristics such as layer crystallinity, epitaxial relationship and surface morphology were investigated by reflection high-energy electron diffraction (RHEED), high-resolution X-ray diffractometer (HRXRD) and atomic force microscope (AFM). Both CeF3 and NdF3 layers of hexagonal structure were grown very conformably on Si(1 1 1) substrates. The ErF3 layer of the native orthorhombic structure could be grown relatively conformably with its crystallites aligned along one of six hexagonally symmetric orientations, whereas the LuF3 layer was degraded in crystalline quality probably due to structural incompatibility and large lattice mismatch with Si(1 1 1) substrate.