Field emission from diameter‐defined single‐walled carbon nanotubes

Irita, Masaru; Homma, Yoshikazu

doi:10.1002/sia.5611

Cited by 3 publications

(1 citation statement)

References 12 publications

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“…This multifaceted seamless one-dimensional roll of a single layer of graphite (graphene) has revealed highly promising applications in future molecular electronics [10,11] over the last few decades. The remarkable electronic properties of these 1-D structures make them suitable for various applications in nanotechnology, optics, electronics, and other fields of materials science as chemical sensors [12][13][14][15][16][17][18][19] , actuators [20] , nano biomaterial [21,22] , conductive heating film [23,24] , conductive transparent electrode [25,26] , conductive nanoink [27] , nano device [28][29][30][31][32] , and display (backlight, flat lamp and field emitter) [32,33] etc. This has invoked interest in the experimentalists as well as theoreticians.…”

Section: Introductionmentioning

confidence: 99%

A theoretical study of (9, 0) Singlewalled Carbon Nanotubes using quantum mechanical techniques

Sharma¹,

Jaggi²

2021

CAN

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First principles simulation studies using the density functional theory have been performed on (9, 0) Zigzag Singlewalled Carbon Nanotube (SWCNT) to investigate its electronic, optical and thermodynamic properties using CASTEP (Cambridge Sequential Total Energy Package) and DFTB (Density Functional based Tight Binding) modules of the Material Studio Software version 7.0. Various functionals and sub-functionals available in the CASTEP Module (using Pulay Density Mixing treatment of electrons) and various eigen-solvers and smearing schemes available in the DFTB module (using smart algorithm) have been tried out to chalk out the electronic structure. The analytically deduced values of the band gap obtained were compared with the experimentally determined value reported in the literature. By comparison, combination of Anderson smearing scheme and standard diaogonalizer produced best results in DFTB module while in the CASTEP module, GGA (General Gradient approximation) functional with RPBE (Revised-perdew-Burke-Ernzerh) as Sub-functional was found to be the most consistent. These optimized parameters were then used to determine various electronic, optical and thermodynamic properties of (9, 0) Singlewalled Nanotube. (9, 0) Singlewalled Nanotube, which is extensively being used for sensing NH3, CH4 & NO2, has been picked up in particular as it is reported to exhibit a finite energy band gap 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.

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Section: Introductionmentioning

confidence: 99%

A theoretical study of (9, 0) Singlewalled Carbon Nanotubes using quantum mechanical techniques

Sharma¹,

Jaggi²

2021

CAN

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Vibrational spectra and phonon dispersion analysis of a single-walled zigzag carbon nanotube: A first principles study

Sharma

Jaggi

2016

Can. J. Phys.

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This paper reports a vibrational spectroscopic study on a zigzag single-walled carbon nanotube (SWCNT) using the first-principles method based on density functional theory (DFT). The most suitable exchange correlation functional for DFT analysis was determined by comparing the predicted value of band gap of the SWCNT under study with the experimental value reported in the literature. General gradient approximation functional in combination with revised Perdew–Burke–Ernzerh sub-functional was found to give the best results. Using this optimum combination, phonon density of states and phonon dispersion curves have been determined. The analysis of results obtained focuses on symmetry considerations, group theory analysis, segregation of Raman active and infrared (IR) active vibrational modes and interpretation of the Raman and IR spectra obtained. The earlier approaches to the problem rely upon the zone folding technique and force constant models in which structural relaxation factor is not taken care of. An ab initio approach has been adopted by the authors in this work, which is advantageous as it neither depends on some predefined parameter nor does it ignore the structural relaxation factor. Analysis of the Raman spectrum reveals some additional peaks other than the commonly known radial breathing mode, D, G, and G′ bands in the SWCNT spectra, which have been recently reported to be observed experimentally also. Similarly, the theoretically developed IR spectrum for the simulated SWCNT is also in agreement with experimental observations. The methodology presented thus provides a very useful and novel simulation route to predict the vibrational modes, Raman spectra, and IR spectra of SWCNTs theoretically.

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Tight binding simulation study on zigzag single-walled carbon nanotubes

Sharma

Jaggi

Gupta

2018

Int. J. Mod. Phys. B

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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.

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Field emission from diameter‐defined single‐walled carbon nanotubes

Cited by 3 publications

References 12 publications

A theoretical study of (9, 0) Singlewalled Carbon Nanotubes using quantum mechanical techniques

A theoretical study of (9, 0) Singlewalled Carbon Nanotubes using quantum mechanical techniques

Vibrational spectra and phonon dispersion analysis of a single-walled zigzag carbon nanotube: A first principles study

Tight binding simulation study on zigzag single-walled carbon nanotubes

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