Measurement of electronic states of PbS nanocrystal quantum dots using scanning tunneling spectroscopy: The role of parity selection rules in optical absorption

Bogdan Diaconescu, Lazaro A. Padilha, Prashant Nagpal, Brian S. Swartzentruber, Victor I Klimov

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

We study the structure of electronic states in individual PbS nanocrystal quantum dots by scanning tunneling spectroscopy (STS) using one-to-two monolayer nanocrystal films treated with 1, 2-ethanedithiols (EDT). Up to six individual valence and conduction band states are resolved for a range of quantum dot sizes. The measured states' energies are in good agreement with calculations using the k·p four-band envelope function formalism. A comparison of STS and optical absorption spectra indicates that some of the absorption features can only be explained by asymmetric transitions involving the states of different symmetries (e.g., S and P or P and D), which points towards the relaxation of the parity selection rules in these nanostructures. STS measurements also reveal a midgap feature, which is likely similar to one observed in previous charge transport studies of EDT-treated quantum dot films.

Original languageEnglish
Article number127406
JournalPhysical Review Letters
Volume110
Issue number12
DOIs
Publication statusPublished - Mar 22 2013

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nanocrystals
parity
optical absorption
quantum dots
scanning
electronics
spectroscopy
optical spectrum
conduction bands
envelopes
formalism
valence
absorption spectra
symmetry
energy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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Measurement of electronic states of PbS nanocrystal quantum dots using scanning tunneling spectroscopy : The role of parity selection rules in optical absorption. / Diaconescu, Bogdan; Padilha, Lazaro A.; Nagpal, Prashant; Swartzentruber, Brian S.; Klimov, Victor I.

In: Physical Review Letters, Vol. 110, No. 12, 127406, 22.03.2013.

Research output: Contribution to journalArticle

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