Interaction of gold nanotubes with the Si(211) surface: A density functional study

Konar, Shyamal; Das, Monoj; Gupta, Bikash C.

doi:10.1103/physrevb.82.125458

Cited by 9 publications

(13 citation statements)

References 34 publications

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“…Within the long-wavelength approximation, the high-temperature relaxation time for piezoelectric scattering can be calculated together with the acoustic phonon scattering as 130 1 Electrons in semiconductors, especially in the inversion layer of electrically gated FET channels, can excite phonons in the surrounding dielectrics via long-range Coulomb interactions, if the dielectrics support polar vibrational modes, as shown in Fig 10d. They are long recognized as 'remote interface phonons' (RIP) or 'surface optical phonons' (SOP) and exist in dielectrics near the inversion layers in silicon 243,244 , organic FETs, [245][246][247] and graphene. [248][249][250][251][252][253] The RIP scattering may not be a significant scattering mechanism in low-field transport or in FETs using low-κ dielectrics, but it can become important at high fields, 253 large inversion densities or high-κ dielectric surroundings, as pointed out by Moore et al 243,244 Experimental studies on organic FETs indicate that the use of high κ dielectric degrades FET carrier mobility. [245][246][247] Table 4 lists the RIP modes for commonly used dielectrics, which are useful for theoretical calculation and device design.…”

Section: Fröhlich and Piezoelectric Interactionsmentioning

confidence: 99%

Charge transport and mobility engineering in two-dimensional transition metal chalcogenide semiconductors

et al. 2016

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Two-dimensional (2D) van der Waals semiconductors represent the thinnest, air stable semiconducting materials known. Their unique optical, electronic and mechanical properties hold great potential for harnessing them as key components in novel applications for electronics and optoelectronics. However, the charge transport behavior in 2D semiconductors is more susceptible to external surroundings (e.g. gaseous adsorbates from air and trapped charges in substrates) and their electronic performance is generally lower than corresponding bulk materials due to the fact that the surface and bulk coincide. In this article, we review recent progress on the charge transport properties and carrier mobility engineering of 2D transition metal chalcogenides, with a particular focus on the markedly high dependence of carrier mobility on thickness. We unveil the origin of this unique thickness dependence and elaborate the devised strategies to master it for carrier mobility optimization. Specifically, physical and chemical methods towards the optimization of the major factors influencing the extrinsic transport such as electrode/semiconductor contacts, interfacial Coulomb impurities and atomic defects are discussed. In particular, the use of ad hoc molecules makes it possible to engineer the interface with the dielectric and heal the vacancies in such materials. By casting fresh light on the theoretical and experimental studies, we provide a guide for improving the electronic performance of 2D semiconductors, with the ultimate goal of achieving technologically viable atomically thin (opto)electronics.

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Section: Fröhlich and Piezoelectric Interactionsmentioning

confidence: 99%

Charge transport and mobility engineering in two-dimensional transition metal chalcogenide semiconductors

et al. 2016

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“…However, the presence of a supporting dielectric substrate significantly reduces the low-field mobility in graphene due to the influence of surface polar phonon (SPP) scattering. [2][3][4][5] While the low-field mobility is reduced, the saturation velocity can be enhanced in supported graphene samples due to the strongly anisotropic nature of SPP scattering. 6 SPP scattering can be also determinant in graphene channels, strongly affecting the current saturation.…”

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confidence: 99%

“…The scattering rates for acoustic and optical phonons considered are derived from ab initio calculations. 15 The anisotropic, inelastic SPP scattering 3,4,6 is implemented in the model taking into account the Fröhlich nature of this kind of interaction, by properly accounting for the angle dependence of the scattering probability integrand. The values of the phonon energies and the low and high frequency dielectric constants for the different substrate materials considered are shown in Table I.…”

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Influence of the substrate on the diffusion coefficient and the momentum relaxation in graphene: The role of surface polar phonons

Rengel

Pascual

Martín

2014

Applied Physics Letters

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Knowing the influence of the substrate type on the diffusion coefficient and the momentum relaxation in graphene is of great importance for the development of new device models specifically adapted to the peculiarities of this material. In this work, the influence of surface polar phonons at low and high electric fields is evaluated by means of ensemble Monte Carlo simulations for several types of substrates. The results show that at low fields surface polar phonons have a major role on reducing the scattering time, breaking the correlation of velocity fluctuations and degrading the diffusion coefficient. At high fields the differences with regard to suspended samples in terms of diffusivity and momentum relaxation tend to reduce, providing at the same time larger saturation velocities, particularly for h-BN. PACS numbers: 72.80.Vp, 72.10.Di, 05.10.Ln a) Electronic mail: raulr@usal.es; The following article appeared in Appl. Phys. Lett. 104, 233107 (2014) and may be found at

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“…[ 143 ] Simulations have shown that high dielectric constant (high-k) materials like these should suppress charged impurity scattering in the underlying graphene, and thus enhance carrier mobility. [144][145][146] Hollander et al [ 147 ] demonstrated a 70% increase in carrier mobility in graphene transistor structures when employing ALD dielectric overlayers in which high-k dielectric seed layers were deposited directly onto epitaxial graphene.…”

Section: Summary Of Literature On Graphene Barrier Layer Experimentsmentioning

confidence: 99%

Review of Graphene as a Solid State Diffusion Barrier

Morrow

Pearton

Ren

2015

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Conventional thin-film diffusion barriers consist of 3D bulk films with high chemical and thermal stability. The purpose of the barrier material is to prevent intermixing or penetration from the two materials that encase it. Adhesion to both top and bottom materials is critical to the success of the barrier. Here, the effectiveness of a single atomic layer of graphene as a solid-state diffusion barrier for common metal schemes used in microelectronics is reviewed, and specific examples are discussed. Initial studies of electrical contacts to graphene show a distinct separation in behavior between metallic groups that strongly or weakly bond to it. The two basic classes of metal reactions with graphene are either physisorbed metals, which bond weakly with graphene, or chemisorbed metals, which bond strongly to graphene. For graphene diffusion barrier testing on Si substrates, an effective barrier can be achieved through the formation of a carbide layer with metals that are chemisorbed. For physisorbed metals, the barrier failure mechanism is loss of adhesion at the metal–graphene interface. A graphene layer encased between two metal layers, in certain cases, can increase the binding energy of both films with graphene, however, certain combinations of metal films are detrimental to the bonding with graphene. While the prospects for graphene's future as a solid-state diffusion barrier are positive, there are open questions, and areas for future research are discussed. A better understanding of the mechanisms which influence graphene's ability to be an effective diffusion barrier in microelectronic applications is required, and additional experiments are needed on a broader range of metals, as well as common metal stack contact structures used in microelectronic applications. The role of defects in the graphene is also a key area, since they will probably influence the barrier properties.

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Interaction of gold nanotubes with the Si(211) surface: A density functional study

Cited by 9 publications

References 34 publications

Charge transport and mobility engineering in two-dimensional transition metal chalcogenide semiconductors

Charge transport and mobility engineering in two-dimensional transition metal chalcogenide semiconductors

Influence of the substrate on the diffusion coefficient and the momentum relaxation in graphene: The role of surface polar phonons

Review of Graphene as a Solid State Diffusion Barrier

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