Optical gain in colloidal quantum dots achieved with direct-current electrical pumping

Jaehoon Lim, Young Shin Park, Victor I. Klimov

Research output: Contribution to journalArticlepeer-review

77 Citations (Scopus)

Abstract

Chemically synthesized semiconductor quantum dots (QDs) can potentially enable solution-processable laser diodes with a wide range of operational wavelengths, yet demonstrations of lasing from the QDs are still at the laboratory stage. An important challenge - realization of lasing with electrical injection - remains unresolved, largely due to fast nonradiative Auger recombination of multicarrier states that represent gain-active species in the QDs. Here we present population inversion and optical gain in colloidal nanocrystals realized with direct-current electrical pumping. Using continuously graded QDs, we achieve a considerable suppression of Auger decay such that it can be outpaced by electrical injection. Further, we apply a special current-focusing device architecture, which allows us to produce high current densities (j) up to ∼18 A cm(-2) without damaging either the QDs or the injection layers. The quantitative analysis of electroluminescence and current-modulated transmission spectra indicates that with j = 3-4 A cm(-2) we achieve the population inversion of the band-edge states.

Original languageEnglish
Pages (from-to)42-48
Number of pages7
JournalNature materials
Volume17
Issue number1
DOIs
Publication statusPublished - Jan 1 2018

ASJC Scopus subject areas

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

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