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Variable-range hopping

About: Variable-range hopping is a(n) research topic. Over the lifetime, 3606 publication(s) have been published within this topic receiving 66561 citation(s).
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Journal ArticleDOI
18 Oct 2007-Nano Letters
TL;DR: Comparison of multilayered sheets revealed that the conductivity of the undermost layer is reduced by a factor of more than 2 as a consequence of the interaction with the Si/SiO2 substrate.
Abstract: Individual graphene oxide sheets subjected to chemical reduction were electrically characterized as a function of temperature and external electric fields. The fully reduced monolayers exhibited conductivities ranging between 0.05 and 2 S/cm and field effect mobilities of 2−200 cm2/Vs at room temperature. Temperature-dependent electrical measurements and Raman spectroscopic investigations suggest that charge transport occurs via variable range hopping between intact graphene islands with sizes on the order of several nanometers. Furthermore, the comparative study of multilayered sheets revealed that the conductivity of the undermost layer is reduced by a factor of more than 2 as a consequence of the interaction with the Si/SiO2 substrate.

2,191 citations


Journal ArticleDOI
Abstract: In a discussion of conduction in glasses containing transition metal ions, the following points are stressed: 1. (a) The process is similar to “impurity conduction” in doped and compensated semi-conductors. 2. (b) There should be two terms in the activation energy, the Miller-Abrahams term and a polaron hopping term. 3. (c) Both terms should tend to zero, giving a decreasing slope of the ln p versus 1/T curve, as T → 0. 4. (d) The Heikes-Ure formula for the thermopower is discussed and a tentative explanation given of the difference between vanadium- and iron-containing glasses.

2,094 citations


Journal ArticleDOI
19 Sep 2011-ACS Nano
TL;DR: It is suggested that Coulomb potential from trapped charges in the substrate is the dominant source of disorder in MoS(2) field-effect devices, which leads to carrier localization, as well, in low-temperature electrical transport experiments.
Abstract: We present low-temperature electrical transport experiments in five field-effect transistor devices consisting of monolayer, bilayer, and trilayer MoS(2) films, mechanically exfoliated onto Si/SiO(2) substrate. Our experiments reveal that the electronic states in all films are localized well up to room temperature over the experimentally accessible range of gate voltage. This manifests in two-dimensional (2D) variable range hopping (VRH) at high temperatures, while below ∼30 K, the conductivity displays oscillatory structures in gate voltage arising from resonant tunneling at the localized sites. From the correlation energy (T(0)) of VRH and gate voltage dependence of conductivity, we suggest that Coulomb potential from trapped charges in the substrate is the dominant source of disorder in MoS(2) field-effect devices, which leads to carrier localization, as well.

762 citations


Journal ArticleDOI
Abstract: We present low temperature electrical transport experiments in five field effect transistor devices consisting of monolayer, bilayer and trilayer MoS2 films, mechanically exfoliated onto Si/SiO2 substrate. Our experiments reveal that the electronic states in all films are localized well up to the room temperature over the experimentally accessible range of gate voltage. This manifests in two dimensional (2D) variable range hopping (VRH) at high temperatures, while below \sim 30 K the conductivity displays oscillatory structures in gate voltage arising from resonant tunneling at the localized sites. From the correlation energy (T0) of VRH and gate voltage dependence of conductivity, we suggest that Coulomb potential from trapped charges in the substrate are the dominant source of disorder in MoS2 field effect devices, which leads to carrier localization as well.

638 citations


Book
01 Jan 1985-
Abstract: Basic Elements of the Theory of Hopping Transport Small Polarons Hopping Conduction in Disordered Systems Classical Hopping Transport Recent Developments Appendix 1. Diagram Technique for Strong Electron-Phonon Coupling Appendix 2. Rate Equation in the Presence of a Magnetic Field Appendix 3. Percolation Problems and the Potts Model References.

561 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20229
202190
202089
2019112
2018103
2017129