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)

Cite this

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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