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Two beam photoluminescence of PbS quantum dots in polyvinyl alcohol

Pendyala, Naresh Babu and Rao, Koteswara KSR (2010) Two beam photoluminescence of PbS quantum dots in polyvinyl alcohol. In: Physica E: Low-dimensional Systems and Nanostructures, 43 (1). pp. 248-251.

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Official URL: http://dx.doi.org/10.1016/j.physe.2010.07.017

Abstract

We report the effect of dual beam excitation on the photoluminescence (PL) from PbS quantum dots in polyvinyl alcohol by using two excitation lasers, namely Ar+ (514.5 nm) and He-Ne laser (670 nm). Both sources of excitation gave similar PL spectra around 1.67 eV (related to shallow traps) and 1.1 eV (related to deep traps). When both lasers were used at the same time, we found that the PL induced by each of the lasers was partly quenched by the illumination of the other laser. The proposed mechanism of this quenching effect involves traps that are populated by one specific laser excitation, being photo-ionized by the presence of the other laser. Temperature, laser intensity and modulation frequency dependent quenching efficiencies are presented in this paper. This reversible modulation has potential for optical switching and memory device applications. (C) 2010 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science B.V.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 21 Mar 2011 09:44
Last Modified: 21 Mar 2011 09:44
URI: http://eprints.iisc.ernet.in/id/eprint/35985

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