Growth and structural characterization of epitaxial (La1−xLux)2O3 layers grown on Si(111)

Abstract

The authors study the growth and structure of epitaxial (La1−xLux)2O3 alloy layers on Si(111) in either homogeneous or digital alloy form. Layer-by-layer growth is achieved by thermal evaporation from La and Lu oxides at a substrate temperature of 700 °C. The grown structures have an abrupt Si/oxide interface as observed by grazing incidence x-ray diffraction and transmission electron microscopy. The in-plane lattice parameter of the (La1−xLux)2O3 reaches values within 0.2% of Si. In-plane lattice constants determined by density functional theory are only slightly off Vegard’s law whereas larger deviations are found for the out-of-plane direction. This may explain the different in-plane lattice constants they measure for digitally or randomly grown (La1−xLux)2O3.