Six novel silicon carbide with direct bandgaps: A comprehensive study

• Published in: Chemical physics 2022-09, Vol.561, p.111603, Article 111603
• Main Authors: Qin, Yingshuo, Chai, Changchun, Si, Zejian, Song, Yanxing, Yang, Yintang
• Format: Article
• Language: English
• Subjects: Density functional theory; Effective mass; Electronic properties; Mechanical properties; SiC phases
• ISSN: 0301-0104
• DOI: 10.1016/j.chemphys.2022.111603

Six new SiC phases with direct bandgaps were found by replacing carbon atoms with carbon and silicon atoms with a stoichiometric ratio of 1:1 in the SACADA-Samara Carbon Allotrope Database of 522 pure carbon structures via the global search method. The six newly discovered SiC phases are in the space groups of Pccn, P4/ncc, Pmn21, P63/m, I4¯3m, and Pnma, in which crystal structures, stabilities, elastic anisotropy, electronic and effective mass were investigated in detail based on first-principles calculations. The formation energies of Pmn21-SiC and Pnma-SiC are very close to that of F4¯3m-SiC, revealing their superiority in experimental implementation. Pccn-SiC, P4/ncc-SiC, Pmn21-SiC, and Pnma-SiC have better compression resistance than F4¯3m-SiC. All the proposed structures are direct bandgap semiconductors with a wide bandgap range of 2.86 ∼ 3.72 eV, which have a smaller effective mass than diamond silicon, giving promising applications in high-frequency, high-temperature and high-power electronic devices.