Engineering the temporal response of photoconductive photodetectors via selective introduction of surface trap states

Gerasimos Konstantatos, Larissa Levina, Armin Fischer, Edward H. Sargent

Research output: Contribution to journalArticlepeer-review

222 Scopus citations

Abstract

Photoconductive photodetectors fabricated using simple solution-processing have recently been shown to exhibit high gains (>1000) and outstanding sensitivities (D* > 1013 Jones). One ostensible disadvantage of exploiting photoconductive gain is that the temporal response is limited by the release of carriers from trap states. Here we show that it is possible to introduce specific chemical species onto the surfaces of colloidal quantum dots to produce only a single, desired trap state having a carefully selected lifetime. In this way we demonstrate a device that exhibits an attractive photoconductive gain >10) combined with a response time (∼25 ms) useful in imaging. We achieve this by preserving a single surface species, lead sulfite, while eliminating lead sulfate and lead carboxylate. In doing so we preserve the outstanding sensitivity of these devices, achieving a specific detectivity of 1012 Jones in the visible, while generating a temporal response suited to imaging applications.

Original languageEnglish (US)
Pages (from-to)1446-1450
Number of pages5
JournalNano letters
Volume8
Issue number5
DOIs
StatePublished - May 2008

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering

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