Thermal shift of the resonance between an electron gas and quantum dots

  • The operation of quantum dots (QDs)at highest possible temperatures is desirable for many applications. Capacitance-voltage spectroscopy(\(\textit {C(V)}\)-spectroscopy) measurements are an established instrument to analyse the electronic structure and energy levels of self-assembled QDs. We perform \(\textit {C(V)}\)in the dark and \(\textit {C(V)}\) under the influence of non-resonant illumination, probing exciton states up to \(X^{4+}\) on InAs QDs embedded in a GaAs matrix for temperatures ranging from 2.5 to 120 K. While a small shift in the charging spectra resonance is observed for the two spin degenerate electron s-state charging voltages with increasing temperature, a huge shift is visible for the electron-hole excitonic states resonance voltages. The \(s_{2}\)-peak moves to slightly higher, the \(s_{1}\)-peak to slightly lower charging voltages. In contrast, the excitonic states are surprisingly charged at much lower voltages upon increasing temperature. We derive a rate-model allowing to attribute and value different contributions to these shifts. Resonant tunnelling, state degeneracy and hole generation rate in combination with the Fermi distribution function turn out to be of great importance for the observed effects. The differences in the shifting behaviour is connected to different equilibria schemes for the peaks-s-peaks arise when tunnelling-in- and out-rates become equal, while excitonic peaks occur, when electron tunnelling-in- and hole-generation rates are balanced.

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Metadaten
Author:Fabian BrinksGND, Andreas D. WieckORCiDGND, Arne LudwigORCiDGND
URN:urn:nbn:de:hbz:294-59010
DOI:https://doi.org/10.1088/1367-2630/aa4f63
Parent Title (English):New journal of physics
Subtitle (English):what is the origin?
Document Type:Article
Language:English
Date of Publication (online):2018/07/11
Date of first Publication:2016/12/15
Publishing Institution:Ruhr-Universität Bochum, Universitätsbibliothek
Tag:Open Access Fonds
71.35.-y; 71.35.Pq; 72.20.Jv; 73.40.Gk; 78.67.Hc; 81.05.Ea; 84.37. + q; III – V semiconductors; capacitance measurement; charge carriers semiconductors and insulators; charged excitons; excitons; quantum dots; resonant tunneling
Volume:18
Issue:12
First Page:123019-1
Last Page:123019-7
Note:
Article Processing Charge funded by the Open Access Publication Fund of Ruhr-Universität Bochum.
Institutes/Facilities:Lehrstuhl für angewandte Festkörperphysik
Dewey Decimal Classification:Naturwissenschaften und Mathematik / Physik
open_access (DINI-Set):open_access
faculties:Fakultät für Physik und Astronomie
Licence (English):License LogoCreative Commons - CC BY 3.0 Unported - Attribution 3.0 Unported