A First Principle Study On P-type Doped 3C-SiC

The wide bandgap semiconductor SiC has many attractive physical properties, which allow applications intended for high temperatures, high frequencies, high power, and harsh chemical environments. At present, many theoretical and experimental investigations of SiC have been carried out on electronic structure, defect states, surface and interface states of SiC. Among the research, much focus on n-type doping and there is little study on the p-type doping. In this paper, the geometrical and electronic structures, the dopant formation energies, lattice constants, band structure and density of states of P-type SiC are calculated by the first principles of plane wave ultra-soft pseudo-potential method based on density functional theory. The mainly contents are as the following:1. The detailed investigations have been carried out, including the geometric and electronic structures, the crystal structure, band structure and density of states of SiC. The results show that SiC is an indirect semiconductor material, its valence band maximum (R point) mainly provided by the 2p of C and 3p of Si. While the conduction band electronic states mainly provided by 3p of Si.2. The geometric structure and electronic structure of SiC doped with B, Al, Ga at the same concentration are investigated. The results of the electronic structure show that the band gap will become narrow with the increase of doping concentration of B and the band gap will become wide with the doping concentration increase of Al and Ga. The results indicate that the band gap of Ga doped with SiC become wider than Al and B at the same concentration.3. The density of states, partial density of states, charge density distribution of B, Al, Ga doped in SiC with different concentrations are investigated, to analyze the microscopic mechanism of the band gap changing when the different dopant doped with different concentration. 4. The magnetic properties of SiC doped with V, Cr, Mn are carried out. The results show that:when V doping on SiC, the lattice parrameters have changed slightly, and had the most stable geometrical structure; when Cr doped SiC, it has the most stable ferromagnetic, followed by Mn, and V is the weakest.