Since c-GaN and ScN have near identical lattice parameters, we have studied the growth of ScN by molecular beam epitaxy, on different surfaces, as a possible buffer layer for improving the quality of c-GaN. Epitaxial growth of ScN on c-GaN(1 0 0), GaAs(1 0 0) and ScAs(1 0 0) surfaces has been demonstrated for the first time. ScN was found to grow in a (100) orientation on ScAs, whereas on c-GaN and GaAs it grew in a (1 1 1) orientation. Epitaxy of GaN on ScN(1 1 1) results in the hexagonal polytype, while GaN on ScN(1 0 0) produces the cubic polytype. AFM studies show smoother surfaces are attained for c-GaN grown on ScN(1 0 0), in comparison to conventional c-GaN growth on GaAs(1 0 0). This shows that ScN(1 0 0) layers offer the potential to improve the quality of c-GaN(I 0 0). (C) 2009 Elsevier B.V. All rights reserved.