Optical properties of SiC nanotubes: A systematic $\text{ab initio}$ study

Abstract

The band structure and optical dielectric function $\epsilon$ of single-walled zigzag [(3,0),(4,0),(5,0),(6,0),(8,0),(9,0),(12,0),(16,0),(20,0),(24,0)], armchair [(3,3),(4,4),(5,5),(8,8),(12,12),(15,15)], and chiral [(4,2),(6,2),(8,4),(10,4)] SiC-NTs as well as the single honeycomb SiC sheet have been calculated within DFT with the LDA. It is found that all the SiC nanotubes are semiconductors, except the ultrasmall (3,0) and (4,0) zigzag tubes which are metallic. Furthermore, the band gap of the zigzag SiC-NTs which is direct, may be reduced from that of the SiC sheet to zero by reducing the diameter ($D$), though the band gap for all the SiC nanotubes with a diameter larger than ~20 Å is almost independent of diameter. For the electric field parallel to the tube axis ($E\parallel \hat{z}$), the ${\epsilon }^{\prime \prime }$ for all the SiC-NTs with a moderate diameter (say, $D$ $>$ 8 Å) in the low-energy region (0~6 eV) consists of a single distinct peak at ~3 eV. However, for the small diameter SiC nanotubes such as the (4,2),(4,4) SiC-NTs, the ${\epsilon }^{\prime \prime }$ spectrum does deviate markedly from this general behavior. In the high-energy region (from 6 eV upwards), the ${\epsilon }^{\prime \prime }$ for all the SiC-NTs exhibit a broad peak centered at ~7 eV. For the electric field perpendicular to the tube axis ($E\perp \hat{z}$), the ${\epsilon }^{\prime \prime }$ spectrum of all the SiC-NTs except the (4,4), (3,0) and (4,0) nanotubes, in the low energy region also consists of a pronounced peak at around 3 eV whilst in the high-energy region is roughly made up of a broad hump starting from 6 eV. The magnitude of the peaks is in general about half of the magnitude of the corresponding ones for $E\parallel \hat{z}$.

References in corpus (3)

• Static dielectric properties of carbon nanotubes from first principles
• Optical absorption and electron energy loss spectra of carbon and boron nitride nanotubes: a first principles approach
• Static dielectric response and Born effective charge of BN nanotubes from {\it ab initio} finite electric field calculations

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• Optical Dielectric Functions of III-V Semiconductors in Wurtzite Phase
• From Half-metal to Semiconductor: Electron-correlation Effects in Zigzag SiC Nanoribbons From First Principles
• Defect-driven tunable electronic and optical properties of two-dimensional silicon carbide
• Band-gap tuning and optical response of two-dimensional Si${}_x$C${}_{1-x}$: A first-principles real space study of disordered 2D materials
• Origin of layer number dependent linear and nonlinear optical properties of two-dimensional graphene-like SiC
• Invariant Wide Bandgaps in Honeycomb Monolayer and Single-Walled Nanotubes of IIB-VI Semiconductors