Plasma-assisted molecular-beam epitaxy of GaN on transition-metal carbide (1 1 1) surfaces

Plasma-assisted molecular beam epitaxy of GaN was studied on (1 1 1) surfaces of several transition-metal carbides (TMC): TiC, ZrC, NbC, and Zr0.2Nb0.8CZr0.2Nb0.8C. On these surfaces, GaN grew epitaxially. Especially, on Zr0.2Nb0.8C(111), which was almost lattice-matched to GaN, a continuous and smooth film was obtained. Viewed from a surface structure perspective, TMC(1 1 1) has a similar metal layer termination to that of ZrB2(0001); consequently, the interface might be similarly stable. The three-fold symmetry of the TMC(1 1 1) is suitable to prevent “anti-phase” boundaries in the grown film.