Engineering the Temporal Response of Photoconductive Photodetectors via Selective Introduction of Surface Trap States
Top Cited Papers
- 2 April 2008
- journal article
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 8 (5), 1446-1450
- https://doi.org/10.1021/nl080373e
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.Keywords
This publication has 10 references indexed in Scilit:
- PbS colloidal quantum dot photoconductive photodetectors: Transport, traps, and gainApplied Physics Letters, 2007
- Sensitive solution-processed visible-wavelength photodetectorsNature Photonics, 2007
- Near-field photodetection with high spatial resolution by nanocrystal quantum dotsOptics Express, 2007
- Ultrasensitive solution-cast quantum dot photodetectorsNature, 2006
- A Lithographic Process for Integrated Organic Field-Effect TransistorsJournal of Display Technology, 2005
- Photodetectors based on treated CdSe quantum-dot filmsApplied Physics Letters, 2005
- Near-infrared fluorescent type II quantum dots for sentinel lymph node mappingNature Biotechnology, 2003
- Charge injection and transport in films of CdSe nanocrystalsJournal of Applied Physics, 2000
- Digital camera system on a chipIEEE Micro, 1998
- Mechanism of Photoconductivity in Chemically Deposited Lead Sulfide LayersJournal of Applied Physics, 1971