Largest Band Gap of All Single Walled Carbon Nanotubes

2003 ◽  
Vol 772 ◽  
Author(s):  
I. Cabria ◽  
J. W. Mintmire ◽  
C. T. White
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Density Functional ◽  
Local Density ◽  
Tight Binding ◽  
Single Walled Carbon Nanotubes ◽  
Theoretical Work ◽  
First Principles Calculations ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

AbstractSingle walled carbon nanotubes, SWNTs, are either semiconducting, metallic, or quasimetallic. Early theoretical work based on tight-binding models predicted that the band gap of semiconducting carbon nanotubes should increase with decreasing radius and this picture was later confirmed by experiment. However, local-density functional calculations indicate that these models are not accurate for narrow carbon nanotubes, where the effects of curvature can convert nanotubes expected to be semiconductors to metals. This raises the question, what is the largest semiconducting band gap possible in a SWNT? We present results from first-principles calculations for a range of carbon nanotubes with radii between 0.15 and 1 nm. These results indicate that the (4,3) carbon nanotube has the largest band gap of all SWNTs.

Energy Band Calculation of Spiral Single-Walled Carbon Nanotubes

2012 ◽  
Vol 535-537 ◽  
pp. 341-344 ◽  
Author(s):  
Hong Xia Wang ◽  
Zi Biao Song ◽  
Dai Zhi Liu
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Electron Energy ◽  
Energy Band ◽  
Structural Parameters ◽  
Tight Binding ◽  
Single Walled Carbon Nanotubes ◽  
Vector Equation ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

On the base of the electron energy band structure of graphene obtained by the tight-binding method, the quantized wave vector equation along the circumferential director of the spiral single-walled carbon nanotubes was established through coordinate transformation and periodic boundary condition, and an analytical expression of the electron energy band was derived. MATLAB is used to calculate the energy band curve of spiral single-walled carbon nanotubes with different structural parameters. The characteristic of the energy band curves was analyzed and discussed. The results shows that single-walled carbon nanotubes (n, m) can be identified as metallic with no band gap nearly which satisfies n-m=3q(q is integer), otherwise, the nanotubes is semiconducting and there are band gaps between conduction band and valence band. And the band gap is inversely proportional to diameter approximately for semiconducting tubes.

THE EFFECTS OF CO-DOPING OF B AND N ON THE ELECTRONIC TRANSPORT OF SINGLE-WALLED CARBON NANOTUBES

2011 ◽  
Vol 25 (14) ◽  
pp. 1211-1218 ◽  
Author(s):  
JIANWEI WEI ◽  
HUI ZENG ◽  
LICHUN PU ◽  
JUNWU LIANG ◽  
HUIFANG HU ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Electronic Transport ◽  
Density Functional ◽  
Covalent Bond ◽  
Single Walled Carbon Nanotubes ◽  
First Principle Calculation ◽  
Single Walled Carbon ◽  
Co Doping ◽  
Walled Carbon Nanotubes

Based on first-principle calculation, the geometry and electronic transport properties of the boron and nitrogen co-doping single-walled carbon nanotubes are investigated by using density functional theory combined with non-equilibrium Green's functions. The results show that the BN atoms energetically tend to form covalent bond of BN along axis in the nanotubes. In contrast to solely B or N doping, the co-doping do not generate accepter or donor subbands near the Fermi level. The co-doping give rise to the reduction of band gap in semiconducting (10, 0) tube and, furthermore, introduces the band gap to the metallic (5, 5) tube.

Tight binding simulation study on zigzag single-walled carbon nanotubes

2018 ◽  
Vol 32 (03) ◽  
pp. 1850020 ◽  
Author(s):  
Deepa Sharma ◽  
Neena Jaggi ◽  
Vishu Gupta
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Tight Binding ◽  
Single Walled Carbon Nanotubes ◽  
Finite Energy ◽  
Model Parameters ◽  
Simulation Studies ◽  
Single Walled Carbon ◽  
Mixing Method ◽  
Walled Carbon Nanotubes

Tight binding simulation studies using the density functional tight binding (DFTB) model have been performed on various zigzag single-walled carbon-nanotubes (SWCNTs) to investigate their electronic properties using DFTB module of the Material Studio Software version 7.0. Various combinations of different eigen-solvers and charge mixing schemes available in the DFTB Module have been tried to chalk out the electronic structure. The analytically deduced values of the bandgap of (9, 0) SWCNT were compared with the experimentally determined value reported in the literature. On comparison, it was found that the tight binding approximations tend to drastically underestimate the bandgap values. However, the combination of Anderson charge mixing method with standard eigensolver when implemented using the smart algorithm was found to produce fairly close results. These optimized model parameters were then used to determine the band structures of various zigzag SWCNTs. (9, 0) Single-walled Nanotube which is extensively being used for sensing NH3, CH4 and NO2 has been picked up as a reference material since its experimental bandgap value has been reported in the literature. It has been found to exhibit a finite energy bandgap in contrast to its expected metallic nature. The study is of utmost significance as it not only probes and validates the simulation route for predicting suitable properties of nanomaterials but also throws light on the comparative efficacy of the different approximation and rationalization quantum mechanical techniques used in simulation studies. Such simulation studies if used intelligently prove to be immensely useful to the material scientists as they not only save time and effort but also pave the way to new experiments by making valuable predictions.

Band-Gap Opening in Metallic Single-Walled Carbon Nanotubes by Encapsulation of an Organic Salt

2017 ◽  
Vol 129 (40) ◽  
pp. 12408-12412
Author(s):  
Belén Nieto-Ortega ◽  
Julia Villalva ◽  
Mariano Vera-Hidalgo ◽  
Luisa Ruiz-González ◽  
Enrique Burzurí ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Single Walled Carbon Nanotubes ◽  
Organic Salt ◽  
Single Walled Carbon ◽  
Gap Opening ◽  
Walled Carbon Nanotubes
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