Growth and properties of scandium epitaxial films on GaN

Epitaxial scandium films have been grown on c-axis-oriented wurtzite GaN. The films are highly ordered, adherent, and reflective. For substrate temperatures in the range 640–780 °C an interfacial reaction yields a ScN layer whose thickness increases with temperature, consistent with Sc diffusion as the rate limiting step. Electrical contacts fabricated from the Sc/ScN/GaN films exhibit a 1.0 eV barrier height on n-type GaN. The Sc films, which represent a class of ductile materials, may constitute a compliant substrate for overgrowth of GaN.