Carrier multiplication in InAs nanocrystal quantum dots with an onset defined by the energy conservation limit

Richard D Schaller, Jeffrey M. Pietryga, Victor I Klimov

Research output: Contribution to journalArticle

236 Citations (Scopus)

Abstract

Carrier multiplication (CM) is a process in which absorption of a single photon produces not just one but multiple electron-hole pairs (excitons). This effect is a potential enabler of next-generation, high-efficiency photovoltaic and photocatatytic systems. On the basis of energy conservation, the minimal photon energy required to activate CM is two energy gaps (2E g). Here, we analyze CM onsets for nanocrystal quantum dots (NQDs) based upon combined requirements imposed by optical selection rules and energy conservation and conclude that materials with a significant difference between electron and hole effective masses such as III-V semiconductors should exhibit a CM threshold near the apparent 2E g limit. Further, we discuss the possibility of achieving sub-2E g CM thresholds through strong exciton-exciton attraction, which is feasible in NQDs. We report experimental studies of exciton dynamics (Auger recombination, intraband relaxation, radiative recombination, multiexciton generation, and biexciton shift) in InAs NQDs and show that they exhibit a CM threshold near 2E g.

Original languageEnglish
Pages (from-to)3469-3476
Number of pages8
JournalNano Letters
Volume7
Issue number11
DOIs
Publication statusPublished - Nov 2007

Fingerprint

energy conservation
multiplication
Excitons
Nanocrystals
Semiconductor quantum dots
Energy conservation
nanocrystals
quantum dots
excitons
Photons
thresholds
Electrons
Energy gap
photons
radiative recombination
attraction
LDS 751
indium arsenide
conservation
requirements

ASJC Scopus subject areas

  • Materials Science(all)
  • Electronic, Optical and Magnetic Materials
  • Chemistry (miscellaneous)

Cite this

Carrier multiplication in InAs nanocrystal quantum dots with an onset defined by the energy conservation limit. / Schaller, Richard D; Pietryga, Jeffrey M.; Klimov, Victor I.

In: Nano Letters, Vol. 7, No. 11, 11.2007, p. 3469-3476.

Research output: Contribution to journalArticle

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