Tuning structural and electronic properties of single-walled SiC nanotubes

The structural and electronic characteristics of the zigzag and armchair single-walled SiC nanotubes have been considered based on density functional theory (DFT). We have studied the effects of tube diameter on the Si-C bond length, the buckling separation, tube lengths, conduction band minimum (CBM), valence band maximum (VBM), Fermi energy, strain energy, and the bandgap. The calculation of strain energy revealed that higher-diameter nanotubes are more stable than those with smaller diameters consequently at the same chirality armchair SiCNTs are more durable than zigzag types. It revealed a correlation between the bandgap and buckling: the smaller the bandgap, the higher the buckling and the buckling separation increased, as the diameter of the tube decreased. The 2p and 3p-orbitals of C and Si atoms contribute the most to CBM and VBM, respectively. All armchairs and zigzag SiCNTs are semiconductors having indirect and direct bandgap, respectively. It also found that the bandgap increased for both zigzag and armchair SiCNTs with increasing diameter of nanotubes. Future research on optoelectronic devices may benefit from the findings of this study.