Energy levels of few-electron quantum dots imaged and characterized by atomic force microscopy

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DOIResolve DOI: http://doi.org/10.1073/pnas.0912716107
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TypeArticle
Journal titlePNAS Early Edition
Volume107
Issue21
Pages16; # of pages: 6
Subjectnanoelectronics; single-electron charging; shell structure; electrostatic force microscopy
AbstractStrong confinement of charges in few-electron systems such as in atoms, molecules, and quantum dots leads to a spectrum of discrete energy levels often shared by several degenerate states. Because the electronic structure is key to understanding their chemical properties, methods that probe these energy levels in situ are important.We show how electrostatic force detection using atomic force microscopy reveals the electronic structure of individual and coupled self-assembled quantum dots. An electron addition spectrum results from a change in cantilever resonance frequency and dissipation when an electron tunnels on/off a dot. The spectra show clear level degeneracies in isolated quantum dots, supported by the quantitative measurement of predicted temperature-dependent shifts of Coulomb blockade peaks. Scanning the surface shows that several quantum dots may reside on what topographically appears to be just one. Relative coupling strengths can be estimated from these images of grouped coupled dots.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada; NRC Institute for Microstructural Sciences
Peer reviewedYes
NPARC number17401041
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Record identifier7211deb8-99d2-4103-8cdb-4356e22415d1
Record created2011-03-29
Record modified2016-05-09
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