The University of Southampton
University of Southampton Institutional Repository

Size dependent carrier recombination in ZnO nanocrystals

Size dependent carrier recombination in ZnO nanocrystals
Size dependent carrier recombination in ZnO nanocrystals
Experimental and theoretical studies of fluorescence decay were performed for colloidal ZnO nanocrystals. The fluorescence lifetime reduces from 22 ps to ∼6 ps∼6 ps with decreasing nanocrystal radius. We postulate that non-radiative surface states dominate the carrier dynamics in small ZnO nanocrystals and perform Monte Carlo simulations incorporating carrier diffusion and carrier recombination to model the experimental fluorescence decay dynamics. The percentage of excitons undergoing nonradiative decay due to surface trapping is as high as 84% for nanocrystals with 8 nm radius, which explains the ultrafast decay dynamics observed in small ZnO nanostructures even at low temperatures.
ZnO is one of the most attractive wide-band gap semiconductors for optoelectronic applications due to its huge exciton binding energy of 60 meV, which allows to design devices operating at temperatures exceeding 300 K. Reduction in physical size to nanoscale offers interesting applications for nanophotonics and nanovoltaics. Low-cost ZnO nanostructures have strong potential for fabrication of light-emitting diodes, nanolasers, nanosized sensors of high sensitivity and field emitters.1–3 Since nanocrystals (NCs) possess a relatively large surface with respect to their volume the influence of surface recombination might be significant for some important applications such as light emitters or solar-cells based on ZnO NCs. From this point of view it is necessary to understand in quantitative terms how the NC size affects the fluorescence properties of ZnO. In this paper, we report results of time-resolved fluorescence studies and model the dynamics using Monte Carlo simulations.
0003-6951
Pozina, G.
83be0072-f18c-4d2b-b38f-77af0336f07c
Yang, L. L.
ae425648-d9a3-4b7d-8abd-b3cfea375bc7
Zhao, Q. X.
18d0b1da-c2be-42d5-90b0-1fef38efc9e2
Hultman, L.
67883278-8ce8-4d2f-8038-141388b2d183
Lagoudakis, P. G.
ea50c228-f006-4edf-8459-60015d961bbf
Pozina, G.
83be0072-f18c-4d2b-b38f-77af0336f07c
Yang, L. L.
ae425648-d9a3-4b7d-8abd-b3cfea375bc7
Zhao, Q. X.
18d0b1da-c2be-42d5-90b0-1fef38efc9e2
Hultman, L.
67883278-8ce8-4d2f-8038-141388b2d183
Lagoudakis, P. G.
ea50c228-f006-4edf-8459-60015d961bbf

Pozina, G., Yang, L. L., Zhao, Q. X., Hultman, L. and Lagoudakis, P. G. (2010) Size dependent carrier recombination in ZnO nanocrystals. Applied Physics Letters, 97 (13). (doi:10.1063/1.3494535).

Record type: Article

Abstract

Experimental and theoretical studies of fluorescence decay were performed for colloidal ZnO nanocrystals. The fluorescence lifetime reduces from 22 ps to ∼6 ps∼6 ps with decreasing nanocrystal radius. We postulate that non-radiative surface states dominate the carrier dynamics in small ZnO nanocrystals and perform Monte Carlo simulations incorporating carrier diffusion and carrier recombination to model the experimental fluorescence decay dynamics. The percentage of excitons undergoing nonradiative decay due to surface trapping is as high as 84% for nanocrystals with 8 nm radius, which explains the ultrafast decay dynamics observed in small ZnO nanostructures even at low temperatures.
ZnO is one of the most attractive wide-band gap semiconductors for optoelectronic applications due to its huge exciton binding energy of 60 meV, which allows to design devices operating at temperatures exceeding 300 K. Reduction in physical size to nanoscale offers interesting applications for nanophotonics and nanovoltaics. Low-cost ZnO nanostructures have strong potential for fabrication of light-emitting diodes, nanolasers, nanosized sensors of high sensitivity and field emitters.1–3 Since nanocrystals (NCs) possess a relatively large surface with respect to their volume the influence of surface recombination might be significant for some important applications such as light emitters or solar-cells based on ZnO NCs. From this point of view it is necessary to understand in quantitative terms how the NC size affects the fluorescence properties of ZnO. In this paper, we report results of time-resolved fluorescence studies and model the dynamics using Monte Carlo simulations.

Full text not available from this repository.

More information

Published date: 27 September 2010

Identifiers

Local EPrints ID: 430537
URI: http://eprints.soton.ac.uk/id/eprint/430537
ISSN: 0003-6951
PURE UUID: 6b3e7910-859a-4be3-930e-f006a2067753
ORCID for L. L. Yang: ORCID iD orcid.org/0000-0002-2032-9327

Catalogue record

Date deposited: 03 May 2019 16:30
Last modified: 29 Oct 2019 02:00

Export record

Altmetrics

Contributors

Author: G. Pozina
Author: L. L. Yang ORCID iD
Author: Q. X. Zhao
Author: L. Hultman

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×