Effect of Interfacial Alloying versus "volume Scaling" on Auger Recombination in Compositionally Graded Semiconductor Quantum Dots

Young Shin Park, Jaehoon Lim, Nikolay S. Makarov, Victor I. Klimov

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Auger recombination is a nonradiative three-particle process wherein the electron-hole recombination energy dissipates as a kinetic energy of a third carrier. Auger decay is enhanced in quantum-dot (QD) forms of semiconductor materials compared to their bulk counterparts. Because this process is detrimental to many prospective applications of the QDs, the development of effective approaches for suppressing Auger recombination has been an important goal in the QD field. One such approach involves "smoothing" of the confinement potential, which suppresses the intraband transition involved in the dissipation of the electron-hole recombination energy. The present study evaluates the effect of increasing "smoothness" of the confinement potential on Auger decay employing a series of CdSe/CdS-based QDs wherein the core and the shell are separated by an intermediate layer of a CdSexS1-x alloy comprised of 1-5 sublayers with a radially tuned composition. As inferred from single-dot measurements, use of the five-step grading scheme allows for strong suppression of Auger decay for both biexcitons and charged excitons. Further, due to nearly identical emissivities of neutral and charged excitons, these QDs exhibit an interesting phenomenon of lifetime blinking for which random fluctuations of a photoluminescence lifetime occur for a nearly constant emission intensity.

Original languageEnglish
Pages (from-to)5607-5613
Number of pages7
JournalNano letters
Volume17
Issue number9
DOIs
Publication statusPublished - Sep 13 2017

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Keywords

  • Semiconductor nanocrystal
  • interfacial alloy layer
  • lifetime blinking
  • quantum dot
  • single-dot spectroscopy
  • suppression of Auger recombination

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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