The effect of charged quantum dots on the mobility of a twodimensional electron gas: How important is the Coulomb scattering?
Abstract
We have investigated the influence of a layer of charged selfassembled quantum dots (QDs) on the mobility of a nearby twodimensional electron gas (2DEG). Timeresolved transconductance spectroscopy was used to separate the two contributions of the change in mobility, which are: (i) The electrons in the QDs act as Coulomb scatterers for the electrons in the 2DEG. (ii) The screening ability and, hence, the mobility of the 2DEG decreases when the charge carrier density is reduced by the charged QDs, i.e., the mobility itself depends on the charge carrier concentration. Surprisingly, we find a negligible influence of the Coulomb scattering on the mobility for a 2DEG, separated by a 30 nm tunneling barrier to the layer of QDs. This means that the mobility change is completely caused by depletion, i.e., reduction of the charge carrier density in the 2DEG, which indirectly influences the mobility.
 Authors:
 Fakultät für Physik and CeNIDE, Universität DuisburgEssen, Lotharstraße 1, Duisburg 47048 (Germany)
 Lehrstuhl für Angewandte Festkörperphysik, RuhrUniversität Bochum, Universitätsstraße 150, 44780 Bochum (Germany)
 Publication Date:
 OSTI Identifier:
 22413052
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CARRIER MOBILITY; CHARGE CARRIERS; CONCENTRATION RATIO; COULOMB SCATTERING; ELECTRIC CONDUCTIVITY; ELECTRON GAS; ELECTRON MOBILITY; LAYERS; QUANTUM DOTS; TIME RESOLUTION; TUNNEL EFFECT; TWODIMENSIONAL CALCULATIONS; TWODIMENSIONAL SYSTEMS
Citation Formats
Kurzmann, A., Email: annika.kurzmann@unidue.de, Beckel, A., Lorke, A., Geller, M., Ludwig, A., and Wieck, A. D. The effect of charged quantum dots on the mobility of a twodimensional electron gas: How important is the Coulomb scattering?. United States: N. p., 2015.
Web. doi:10.1063/1.4907217.
Kurzmann, A., Email: annika.kurzmann@unidue.de, Beckel, A., Lorke, A., Geller, M., Ludwig, A., & Wieck, A. D. The effect of charged quantum dots on the mobility of a twodimensional electron gas: How important is the Coulomb scattering?. United States. doi:10.1063/1.4907217.
Kurzmann, A., Email: annika.kurzmann@unidue.de, Beckel, A., Lorke, A., Geller, M., Ludwig, A., and Wieck, A. D. 2015.
"The effect of charged quantum dots on the mobility of a twodimensional electron gas: How important is the Coulomb scattering?". United States.
doi:10.1063/1.4907217.
@article{osti_22413052,
title = {The effect of charged quantum dots on the mobility of a twodimensional electron gas: How important is the Coulomb scattering?},
author = {Kurzmann, A., Email: annika.kurzmann@unidue.de and Beckel, A. and Lorke, A. and Geller, M. and Ludwig, A. and Wieck, A. D.},
abstractNote = {We have investigated the influence of a layer of charged selfassembled quantum dots (QDs) on the mobility of a nearby twodimensional electron gas (2DEG). Timeresolved transconductance spectroscopy was used to separate the two contributions of the change in mobility, which are: (i) The electrons in the QDs act as Coulomb scatterers for the electrons in the 2DEG. (ii) The screening ability and, hence, the mobility of the 2DEG decreases when the charge carrier density is reduced by the charged QDs, i.e., the mobility itself depends on the charge carrier concentration. Surprisingly, we find a negligible influence of the Coulomb scattering on the mobility for a 2DEG, separated by a 30 nm tunneling barrier to the layer of QDs. This means that the mobility change is completely caused by depletion, i.e., reduction of the charge carrier density in the 2DEG, which indirectly influences the mobility.},
doi = {10.1063/1.4907217},
journal = {Journal of Applied Physics},
number = 5,
volume = 117,
place = {United States},
year = 2015,
month = 2
}

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