First-principles study of boron doping-induced band gap narrowing in 3C-SiC

Based on density functional theory (DFT), the effect of boron (B) doping concentration on band gap of 3C-SiC is investigated. The analysis of density of states (DOS) and electron distribution indicates that the band gap tends to narrow with the increase of B concentration. The top of valence band, is contributed from B 2p level, and the bottom of conduction band, from B 2s in B-doped 3C-SiC. Both of them shift towards lower energy direction. With B concentration increases, the displacement of the bottom of conduction band is larger than that of the top of valence band, resulting in the narrowing of band gap. This result is useful for controlling band gap of doped 3C-SiC, and should be helpful for enhancing reliability and broadening the application ranges of SiC devices.