Size- and surface-dependent electronic structures of crystalline SiC nanotubes

作者：Zhou, R L^*; Zuo, R Z; Wang, L; Zhang, B H; Pan, B C

来源：Journal of Applied Physics, 2011, 109(8): 084318.

DOI：10.1063/1.3567114

• Application prospect
• Direct band gap
• Hydrogen atoms
• Optoelectronic properties
• Quantum confinement effects
• Surface effect
• Surface saturation
• Wall thickness

In this paper, the dependence of the stability and electronic structures of single-crystal 2H SiC and 3C SiC nanotubes on the sizes, surface facets, and surface saturation conditions are investigated with the help of density functional theory. The stabilities of each type of SiC nanotube increase as the wall-thicknesses increase no matter whether the surfaces are bare or saturated with hydrogen atoms. 2H SiC nanotubes are energetically more stable than 3C SiC nanotubes. The band gaps of each type of SiC nanotube decrease uniformly as the wall thicknesses increase when they are fully saturated or outer saturated with H atoms, while they increase uniformly when they are bare. The different trends of band gaps for bare and H-saturated SiC nanotubes reflect the competition between the quantum confinement effects and surface effects. Surface saturation can largely increase the band gaps especially for 2H SiC nanotubes. All the nanotubes possess direct band gaps when they are fully saturated with hydrogen atoms while most of them possess indirect ones when they are bare or half saturated. However, the bare or half-saturated single-crystal SiC nanotubes may also possess good optoelectronic properties because the top valance bands and bottom conduction bands are much flatter. Our results indicate that single-crystal SiC nanotubes, especially 2H SiC nanotubes, may have wider application prospects in optoelectronic devices.

• 出版日期2011-4-15
• 单位合肥工业大学; 中国科学技术大学