Chirality Dependence of Electron Transport Properties of Single-Walled GeC Nanotubes

Samanta, Pabitra Narayan; Das, Kalyan Kumar

doi:10.1021/jp306526b

Cited by 11 publications

(6 citation statements)

References 45 publications

(56 reference statements)

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“…However, at the higher voltage 1.6 V, a couple of broad peaks appear and the current increases steadily. The observed NDR effect is, therefore responsible for the suppression of conduction channel at a certain bias, which is in accordance with the NDR mechanism, as shown by other nanodevices like GeCNT, 35 SnCNT, 36 and C 60 molecular devices. 44 To gain a further insight into the origin of NDR, we also calculated the PDOS of Ge and Si atoms for (4,0) SiGeNT under +0.2, +0.8, and +1.6 V, shown in Figure 7.…”

Section: Resultssupporting

confidence: 87%

“…20 As reported by these authors, SiGe nanotubes in the zigzag form have lower band gaps compared with these in the armchair conformation possibly due to delocalized nature of the electrons. It may be mentioned that SiCNTs, GeCNTs, and SnCNTs have different band structures, 35,36 and their dependences on chirality are also somewhat different. Electronic density of states (DOS) has been calculated to confirm the nature of transmission through SiGeNTs of four different chiralities.…”

Section: Resultsmentioning

confidence: 99%

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Electronic-Transport Properties of Single-Walled Zigzag SiGe Nanotubes

Samanta

Das

2014

J. Phys. Chem. C

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Electronic-transport properties of zigzag singlewalled SiGe nanotubes of four different chiralities are studied by using density functional theory combined with nonequilibrium Green's function formalism. Band structures of (n,0) SiGeNTs (n = 4−7) are computed using 1 × 1 × 100 kpoint sampling. Transmission coefficients of these devices are estimated at various positive and negative bias voltages within ±2.0 V. The (4,0) SiGeNT shows metallic character, while the high-chiral (7,0) nanotube is expected to be of the semiconducting type. The current−voltage (I−V) curves of these systems are constructed for different bias voltages. Except (6,0) nanotube, all SiGe nanotubes show negative differential resistance, which is explained from the appearance or disappearance of transmission peaks within the bias window. The dependence of the length of the central region on the I−V characteristic has been tested on (4,0) SiGeNT using three-and four-cell tubes. As the length of the central region increases, the peak-to-valley ratio of the I−V curve increases from 1.92 to 5.32; however, the nature of the curves remains almost the same. The rectifying performances of these devices are investigated by calculating the rectification ratio (I + /I − ).

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Electronic-Transport Properties of Single-Walled Zigzag SiGe Nanotubes

Samanta

Das

2014

J. Phys. Chem. C

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“…Moreover, many studies show that the magnetic properties of GeC can be tuned by surface functionalization 30 , foreign atom adsorption 27 and defects generation 31 . In addition, First principles calculations were also performed to understand the electronic and magnetic properties of GeC nanotubes 32 – 36 . Besides, the good stability of GeC monolayer has been demonstrated by the phonon dispersion 25 .…”

Section: Introductionmentioning

confidence: 99%

Tunable Schottky barrier in graphene/graphene-like germanium carbide van der Waals heterostructure

Wang

Chou

Ren

et al. 2019

Sci Rep

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The structural and electronic properties of van der Waals (vdW) heterostructrue constructed by graphene and graphene-like germanium carbide were investigated by computations based on density functional theory with vdW correction. The results showed that the Dirac cone in graphene can be quite well-preserved in the vdW heterostructure. The graphene/graphene-like germanium carbide interface forms a p-type Schottky contact. The p-type Schottky barrier height decreases as the interlayer distance decreases and finally the contact transforms into a p-type Ohmic contact, suggesting that the Schottky barrier can be effectively tuned by changing the interlayer distance in the vdW heterostructure. In addition, it is also possible to modulate the Schottky barrier in the graphene/graphene-like germanium carbide vdW heterostructure by applying a perpendicular electric field. In particular, the positive electric field induces a p-type Ohmic contact, while the negative electric field results in the transition from a p-type to an n-type Schottky contact. Our results demonstrate that controlling the interlayer distance and applying a perpendicular electric field are two promising methods for tuning the electronic properties of the graphene/graphene-like germanium carbide vdW heterostructure, and they can yield dynamic switching among p-type Ohmic contact, p-type Schottky contact, and n-type Schottky contact in a single graphene-based nanoelectronics device.

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“…Besides SiCNT, the armchair germanium carbide nanotubes (GeCNTs) are also known to have semiconducting properties with large band gaps . Recent calculations based on DFT and nonequilibrium Green function (NEGF) have predicted the existence of negative differential resistance, which depends on the chirality of the zigzag GeCNTs. The adsorption sensitivities of (6,0) GeCNT toward small molecules have also been tested at the ONIOM (B3LYP/6‐311++G(d,p)//LANL2DZ:UFF) level of calculation…”

Section: Introductionmentioning

confidence: 99%

QM/MM study of the interaction between zigzag SnC nanotube and small toxic gas molecules

Samanta

Das

2015

Int. J. Quantum Chem.

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Adsorptions of small toxic molecules such as CO, N 2 , HCN, SO 2 , H 2 CO, and NH 3 on a single-walled (6,0) SnC nanotube (SnCNT) are investigated using Quantum Mechanics/Molecular Mechanics (QM/MM) methodology. The calculations are carried out at the B3LYP/6-31111G(d,p)//LANL2DZ:UFF level of theory. The high layer of the model consists of a pyrene-type ring on the nanotube surface as the adsorption site, where one gas molecule is allowed to interact. Conversely, for the adsorption of the two molecules, a larger site like a coronene ring is used for the high layer. Adsorption energy, Gibbs free energy change, Mulliken charge transfer, and total electron-density maps are computed in each case. The adsorption strength of the gas molecule on the SnCNT surface is also analyzed from the density of states projected to different atoms (PDOS) of the nanotube-adsorbate complexes. The adsorptions of CO and N 2 on the (6,0) SnCNT surface require to cross potential barriers, and the corresponding transition structures are identified by ONIOM-IRC calculations. For the remaining four molecules, the processes of adsorption are predicted to be barrier-less. The calculations for the adsorption of H 2 CO on (5,0) and (7,0) SnCNT surfaces are extended to study the effect of the size of the nanotube. Results for the adsorption of a single molecule on (6,0) SnCNT using B3LYP functional are compared with those obtained from a dispersion corrected functional such as M06-2X.

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Chirality Dependence of Electron Transport Properties of Single-Walled GeC Nanotubes

Cited by 11 publications

References 45 publications

Electronic-Transport Properties of Single-Walled Zigzag SiGe Nanotubes

Electronic-Transport Properties of Single-Walled Zigzag SiGe Nanotubes

Tunable Schottky barrier in graphene/graphene-like germanium carbide van der Waals heterostructure

QM/MM study of the interaction between zigzag SnC nanotube and small toxic gas molecules

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