From a thermodynamics perspective, the surface energy of the C-face of silicon carbides polytype is lower (7.5 J/m 2 ) than that of the Si-face (18 J/m 2 ) . To our knowledge, there are no computed data the surface energy for all r-B4C facets. Nevertheless, considering the surface energy for boron carbide for the (101 ̅ 1) planes (3.21 J/m 2 26 , 3.27 J/m ) and the surface energy for α-boron facets (1.9 to 3.6 J/m 2 ) , having a similar structure as r-B4C, differing only in the absence the triatomic chains, one can conclude that they are lower than the surface energy of the C-face of 4H-SiC. Assuming the interfacial energy to be small for (0001)-oriented B4C crystals on SiC(0001) and SiC(0001 ̅ ) due to the small lattice mismatch, one would expect that both surfaces would allow epitaxial growth; although it can be argued that the surface energy of SiC(0001) is so high that multiple orientations of B4C could grow in-spite of a higher interfacial energy, hence leading to polycrystalline growth. The issue with these energetic considerations is that they might not be valid at our growth conditions.