How quickly does a hole relax into an engineered defect state in CDSE quantum dots

Assaf Avidan, Iddo Pinkas, Dan Oron

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Intraband hole relaxation of colloidal Te-doped CdSe quantum dots is studied using state-selective transient absorption spectroscopy. The dots are excited at the band edge, and the defect band bleach caused by state filling of the hole is probed. Close to the defect energy, the hole relaxation is substantially slowed down, indicating a gap separating the defect state from the CdSe band edge. A clear dependence of the relaxation time with the QDs size is presented, implying that the hole relaxation is mediated by longitudinal optical (LO) phonon modes of the CdSe host. In addition, we find that overcoating the quantum dots by two monolayers of a ZnS shell extends the hole relaxation time by a factor of 2, suggesting a combined effect of LO phonons and surface effects governing intraband hole relaxation.

Original languageEnglish
Pages (from-to)3063-3069
Number of pages7
JournalACS nano
Volume6
Issue number4
DOIs
Publication statusPublished - Apr 24 2012

Keywords

  • LO phonons
  • cooling
  • doping
  • holes
  • quantum dots

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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