The semi-empirical tight-binding model for carbon allotropes “between diamond and graphite”

Lytovchenko, V.G.; Kurchak, Anatolii I.; Стріха, М. В.

doi:10.1063/1.4885060

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…The model described in this paper also makes it possible to estimate a potential capability to create Gunn diodes on the basis of other 2D semiconductor monolayers and thin quantum wells, which are based on both traditional electronic materials and carbon allotropes "between graphene and graphite". The latter, as we showed in work [11], can also possess useful semiconductor properties.…”

Section: Theoretical Model For Negative Differential Conductance In 2mentioning

confidence: 61%

Theoretical Model for Negative Differential Conductance in 2D Semiconductor Monolayers

Lytovchenko¹,

Kurchak²,

Стріха³

2018

Ukr. J. Phys.

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A simple theoretical model of electron heating in a system with two valleys is applied for the first time to describe 2D semiconductor monolayers of the MoS2 and WS2 types. The model is demonstrated to describe sufficiently well the available experimental data on the negative differential conductance effect in a WS2 monolayer. It confirms a possibility to fabricate Gunn diodes of a new generation based on the structures concerned. Such diodes are capable of generating frequencies of an order of 10 GHz and higher, which makes them attractive for many practical applications. A carbon atomic monolayer, graphene, was obtained for the first time in 2004. It was found to be semimetal [1]. Therefore, its parameters can hardly be used to implement essentially different states "0" and "1", which became a principal obstacle on the way to the creation of the graphene-based hardware components for new electronics. Numerous attempts to induce semiconductor-like properties in graphene (by the hydrogenation, creation of nanostripes, inserting defects, and so forth; see work [2] and references therein) turned out unsuccessful from the viewpoint of further practical applications.However, during last years, other monolayers with semiconducting properties (MoS 2 , WSe 2 , and other chalcogenides of transition metals, black phosphorus, and others; see, e.g., works [3,4]) were intensively synthesized and studied. The most known from this class of materials are the MoS 2 and WS 2 monolayers. They are direct-band semiconductors with the band gap widths ≈ 1.7 and 1.8 eV, respectively. The extrema of the conduction and valence bands are located at points and ′ of the hexagonal Brillouin zone [5], as it takes place in graphene.The results of calculations carried out from the first principles, by using the density functional method demonstrated that the conduction band spectrum of those materials includes a lateral extremum (the -valley) with energies by approximately 0.2 and 0.08 eV larger than the band bottom energy, which is located in the direction from the points and ′ to the Brillouin zone center Γ (Fig. 1). The energy spectrum near those two extrema is parabolic. The presence of two subbands in the conduction bandlower (denoted by subscript 1) and upper (denoted by subscript 2) ones, for which the effective-mass relation 1 < 2 for two-dimensional electrons is obeyed [5] -gives us grounds to expect that the effect of negative differential conductance, which is associated with the filling by field-heated electrons of the higher val-

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Section: Theoretical Model For Negative Differential Conductance In 2mentioning

confidence: 61%

Theoretical Model for Negative Differential Conductance in 2D Semiconductor Monolayers

Lytovchenko¹,

Kurchak²,

Стріха³

2018

Ukr. J. Phys.

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show abstract

“…The model described in this paper also makes it possible to estimate a potential capability to create Gunn diodes on the basis of other 2D semiconductor monolayers and thin quantum wells, which are based on both traditional electronic materials and carbon allotropes "between graphene and graphite". The latter, as we showed in work [20], can also possess useful semiconductor properties.…”

Section: Electronic 2d Devices Based On Hot Electrons (2d Generators mentioning

confidence: 63%

2D semiconductor structures as a basis for new high-tech devices (Review)

Korbutyak¹

2018

Semicond. Phys. Quantum Electron. Optoelectron

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In this article, we present a short overview of the Ukrainian contribution into physics of 2D semiconductor structures as a basis for high-tech devices of modern nanoelectronics together with some new results in this field. The possibility of creating "low-threshold" 2D lasers in Si 3 N 4-GaAs and Al x Ga 1-x As-GaAs layered heterostructures, in which two-dimensional electron-hole plasma (EHP) is formed, has been analyzed. The investigations of optical amplification spectra in heterostructures with a two-dimensional quantum well have been performed in details. It has been demonstrated that under the conditions of simultaneous coexistence of 3D-EHP and 2D-EHP, stimulated radiation is formed predominantly in 2D-EHP, with the laser excitation threshold at which optical amplification occurs in 2D-EHP by two orders of magnitude lower than in 3D-EHP, and the corresponding value of the coefficient of optical amplification is 2.5 times greater. A simple theoretical model of electron heating in a system with two valleys is applied to describe 2D semiconductor monolayers of the MoS 2 and WS 2 types. The model is demonstrated to describe sufficiently well the available experimental data on the negative differential conductance effect in a WS 2 monolayer. It confirms the possibility to fabricate Gunn diodes of a new and advanced EMW generation based on the structures concerned. These diodes are capable to generate frequencies of the order of 10 GHz and higher, which makes them attractive for HF practical applications.

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“…The calculations of the electron affinity 0 involving the structural point defects, as well as some atoms of impurities in the graphite and DLC ultrathin films, were performed by the creation of hybride configurations with regard for the energies of and valence orbitals and a change of the interatomic distances [15][16][17]. To calculate this parameter, the following formulas, which include the energy of valence bond , the energy of metallic bond , the energy of ionic bond , as well as the geometrical parameter (the size of a cluster), have been used [15][16][17]:…”

Section: Modelingmentioning

confidence: 99%

Conductive Nanorods in DLC Films Caused by Carbon Transformation

et al. 2017

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The influence of diamond-like carbon (DLC) films deposited under various conditions on the electron field emission (EFE) of silicon (Si) tips has been investigated. During the nitrogendoped DLC film deposition, the nitrogen content in a gas mixture is varied from 0% to 45%. In this context, the effective work function is optimized, by reaching the values less than 1 eV. A sharp increase in the emission current at high electric fields and a decrease of the threshold voltage after the pre-breakdown conditioning of a DLC film on Si tips have been measured. At high current densities and the resulting local heating, the diamond-like 3 phase transforms into a conducting graphite-like 2 phase. As a result, an electrical conducting nanostructured channel is formed in the DLC film. The diameter of the conducting nanochannel is estimated from the reduced threshold voltage after the pre-breakdown conditioning to be in the interval 5-25 nm. The presence of this nanochannel in the insulating matrix leads to a local enhancement of the electric field and a reduced threshold voltage for EFE. The obtained results can be used for the development of highly efficient field emission cathodes. To explain the experimental EFE results based on a transformation of DLC films and the generation of conduction nanochannels, the changes of the electron affinity (0) for various carbon structures and impurity point defects have been calculated. The influence of the rehybridization of bonds in various carbon crystal structures on 0 is shown. The formation of conducting channel arrays in DLC films will allow us to significantly enhance EFE even on flat surfaces without tips. K e y w o r d s: diamond-like carbon film, electron field emission, conductive nanorods, carbon nanotube.

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The semi-empirical tight-binding model for carbon allotropes “between diamond and graphite”

Cited by 4 publications

References 10 publications

Theoretical Model for Negative Differential Conductance in 2D Semiconductor Monolayers

Theoretical Model for Negative Differential Conductance in 2D Semiconductor Monolayers

2D semiconductor structures as a basis for new high-tech devices (Review)

Conductive Nanorods in DLC Films Caused by Carbon Transformation

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