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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.
- Source :
-
Physical Review Letters . 3/22/2013, Vol. 110 Issue 12, p127406-1-127406-5. 5p. - Publication Year :
- 2013
-
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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00319007
- Volume :
- 110
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Physical Review Letters
- Publication Type :
- Academic Journal
- Accession number :
- 86874212
- Full Text :
- https://doi.org/10.1103/PhysRevLett.110.127406