Electric fields at the SiC/AlN and SiC/GaN polar interfaces

Abstract

We present first-principles calculations of structural and electronic properties of heterovalent SiC/AlN and SiC/GaN heterostructures with wurtzite AlN and GaN films pseudomorphically grown on the 6H-SiC and 3C-SiC substrates along the c-axis. We have investigated reconstructed stoichiometric interfaces consisting of one mixed layer with various lateral arrangements. The preferred bonding configurations of the reconstructed interfaces are found to be Si-N and Ga-C. The calculated valence band discontinuities for SiC/AlN and SiC/GaN heterostructures lie in the range of 1.5 - 2.3 eV and 0.4 - 1.4 eV, respectively. The SiC/AlN heterostructures are predicted to be of type I, whereas SiC/GaN heterostructures can be of type I or II. The polarization induced interface charges are of the order of 4.8 × 1012cm−2 and 0.7 × 1012 cm−2 in SiC/AlN and SiC/GaN junctions, respectively.

Ab Initio Studies of Al and Ga Adsorption on 4H-SiC{0001} Surfaces

“…The cuto of 120 Ry was used for the real space mesh. The Brillouin zone integrations were performed applying the (8,8,2) and (8,8,1) k-points meshes for bulk and surface calculations, respectively. The 4H-SiC crystal was represented by a hexagonal supercell containing eight atoms that was repeated periodically in space.…”