Simulation of the Band Structure of Graphene and Carbon Nanotube

Mina, Aziz N.; Awadallah, Attia A; Phillips, Adel H.; Ahmed, Riham R.

doi:10.1088/1742-6596/343/1/012076

Cited by 7 publications

(11 citation statements)

References 25 publications

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“…Therefore, in the present paper, we use a value of the axial tensile strain of 0.1. Accordingly, the values of the energy gap in the present investigated paper (Table 1) are in good agreement with those published for semiconducting SWCNT [11,12,22,24,25].…”

Section: Discussionsupporting

confidence: 91%

“…The variation of the energy band gap of all types of SWCNT with strain might be due to the breaking of the bond symmetry due to curvature of the three types of SWCNTs [11,12,36,37]. It is well known [21,24,25] that the in-plane C-C bond is a strong covalent σ bond, so the SWCNTs acquire a high elastic modulus along the axial direction. The authors [38][39][40] show that the maximum elastic tensile strain for SWCNTs is in the range 0.1-0.13 when studying mechanical properties of it.…”

Section: Discussionmentioning

confidence: 99%

“…The thermo-power (Seebeck coefficient), S, and the Peltier coefficient (Π) are expressed in terms of the function L m (µ), as follows [2,13,14] The chiral vector (C h ) is expressed in terms of the chiral indices n and m as [21][22][23]: (14) In the present paper we consider an armchair SWCNT, a zigzag SWCNT, and a chiral SWCNT; that is, for the armchair carbon nanotube n = m, while for zigzag carbon nanotube m = 0 [21][22][23], and for the chiral carbon nanotube with chiral indices n and m [24,25].…”

Section: The Modelmentioning

confidence: 99%

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Thermoelectric Seebeck and Peltier effects of single walled carbon nanotube quantum dot nanodevice

El-Demsisy¹,

Asham²,

Louis³

et al. 2017

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The thermoelectric Seebeck and Peltier effects of a single walled carbon nanotube (SWCNT) quantum dot nanodevice are investigated, taking into consideration a certain value of applied tensile strain and induced ac-field with frequency in the terahertz (THz) range. This device is modeled as a SWCNT quantum dot connected to metallic leads. These two metallic leads operate as a source and a drain. In this three-terminal device, the conducting substance is the gate electrode. Another metallic gate is used to govern the electrostatics and the switching of the carbon nanotube channel. The substances at the carbon nanotube quantum dot/ metal contact are controlled by the back gate. Results show that both the Seebeck and Peltier coefficients have random oscillation as a function of gate voltage in the Coulomb blockade regime for all types of SWCNT quantum dots. Also, the values of both the Seebeck and Peltier coefficients are enhanced, mainly due to the induced tensile strain. Results show that the three types of SWCNT quantum dot are good thermoelectric nanodevices for energy harvesting (Seebeck effect) and good coolers for nanoelectronic devices (Peltier effect).

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: The Modelmentioning

confidence: 99%

See 1 more Smart Citation

Thermoelectric Seebeck and Peltier effects of single walled carbon nanotube quantum dot nanodevice

El-Demsisy¹,

Asham²,

Louis³

et al. 2017

Carbon letters

View full text Add to dashboard Cite

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“…Due to its gapless band-structure, with the valence and conduction bands touching each other at the socalled Dirac points, graphene originates ambipolar field-effect transistors with V-shaped transfer characteristics, dominated by a p-branch at negative and n-type conduction at positive gate voltage [52]. The ambipolar conduction can be an important feature for complementary logic applications; however, the limited on/off ratio caused by the absence of intrinsic bandgap is a significant obstacle and requires delicate material engineering for real applications [53][54][55].…”

Section: Introductionmentioning

confidence: 99%

Contact resistance and mobility in back-gate graphene transistors

et al. 2020

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The metal-graphene contact resistance is one of the major limiting factors toward the technological exploitation of graphene in electronic devices and sensors. High contact resistance can be detrimental to device performance and spoil the intrinsic great properties of graphene. In this paper, we fabricate back-gate graphene field-effect transistors with different geometries to study the contact and channel resistance as well as the carrier mobility as a function of gate voltage and temperature. We apply the transfer length method and the y-function method showing that the two approaches can complement each other to evaluate the contact resistance and prevent artifacts in the estimation of carrier mobility dependence on the gate-voltage. We find that the gate voltage modulates both the contact and the channel resistance in a similar way but does not change the carrier mobility. We also show that raising the temperature lowers the carrier mobility, has a negligible effect on the contact resistance, and can induce a transition from a semiconducting to a metallic behavior of the graphene sheet resistance, depending on the applied gate voltage. Finally, we show that eliminating the detrimental effects of the contact resistance on the transistor channel current almost doubles the carrier field-effect mobility and that a competitive contact resistance as low as 700 Ω·μm can be achieved by the zig-zag shaping of the Ni contact.

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“…Recent progress in the area of two-dimensional (2D) materials such as graphene 1 and MoS2 2 has sparked interest within the research community due to extraordinary properties that have potential for transformative technologies. 2D materials offer superior properties to their bulk counterparts, with higher photosensitivity, 3 tunable band structures and band gaps, 4,5 and increased exciton annihilation efficiency. [6][7][8] 2D semiconductors provide immense potential to satisfy the need to decrease microelectronics size; however, there are strong limitations on material composition due to desires to integrate materials which are currently established in our electronics infrastructure.…”

Section: ■ Introductionmentioning

confidence: 99%

Silicene, Siloxene, or Silicane? Revealing the Structure and Optical Properties of Silicon Nanosheets Derived from Calcium Disilicide

et al. 2019

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Si-nanosheets (Si-NSs) have recently attracted considerable attention due to their potential as nextgeneration materials for electronic, optoelectronic, spintronic, and catalytic applications. Even though monolayer Si-NSs were first synthesized over 150 years ago via topotactic deintercalation of CaSi2, there is a lack of consensus within the literature regarding the structure and optical properties of this material. Herein, we provide conclusive evidence of the structural and chemical properties of Si-NSs produced by the deintercalation of CaSi2 with cold (~-30 °C) aqueous HCl, and characterize their optical properties. We use a wide range of techniques, including XRD, FTIR, Raman, solid-state NMR, SEM, TEM, EDS, XPS, diffuse reflectance absorbance, steady-state photoluminescence, time-resolved photoluminescence, and thermal decomposition; combined together, these techniques enable unique insight into the structural and optical properties of the Si-NSs. Additionally, we support the experimental findings with density functional theory (DFT) calculations to simulate FTIR, Raman, NMR, interband electronic transitions, and band structures. We determined that the Si-NSs consist of buckled Si monolayers that are primarily monohydride terminated. We characterize the nanosheets' optical properties, finding they have a band gap of ~2.5 eV with direct-like behavior and an estimated quantum yield of ~9%. Given the technological importance of Si, these results are encouraging for a variety of optoelectronic technologies, such as phosphors, light-emitting diodes, and CMOS-compatible photonics. Our results provide critical structural and optical properties to help guide the research community in integrating Si-NSs into optoelectronic and quantum devices. Disciplines Disciplines Materials Chemistry Comments Comments

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Simulation of the Band Structure of Graphene and Carbon Nanotube

Cited by 7 publications

References 25 publications

Thermoelectric Seebeck and Peltier effects of single walled carbon nanotube quantum dot nanodevice

Thermoelectric Seebeck and Peltier effects of single walled carbon nanotube quantum dot nanodevice

Contact resistance and mobility in back-gate graphene transistors

Silicene, Siloxene, or Silicane? Revealing the Structure and Optical Properties of Silicon Nanosheets Derived from Calcium Disilicide

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