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The role of quantum-confined excitons vs defects in the visible luminescence of SiO2 films containing Ge nanocrystals

Min, K. S. and Shcheglov, K. V. and Yang, C. M. and Atwater, Harry A. and Brongersma, M. L. and Polman, A. (1996) The role of quantum-confined excitons vs defects in the visible luminescence of SiO2 films containing Ge nanocrystals. Applied Physics Letters, 68 (18). pp. 2511-2513. ISSN 0003-6951. http://resolver.caltech.edu/CaltechAUTHORS:MINapl96a

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Abstract

Synthesis of Ge nanocrystals in SiO2 films is carried out by precipitation from a supersaturated solid solution of Ge in SiO2 made by Ge ion implantation. The films exhibit strong room-temperature visible photoluminescence. The measured photoluminescence peak energy and lifetimes show poor correlations with nanocrystal size compared to calculations involving radiative recombination of quantum-confined excitons in Ge quantum dots. In addition, the photoluminescence spectra and lifetime measurements show only a weak temperature dependence. These observations strongly suggest that the observed visible luminescence in our samples is not due to the radiative recombination of quantum-confined excitons in Ge nanocrystals. Instead, observations of similar luminescence in Xe+ -implanted samples and reversible PL quenching by hydrogen or deuterium suggest that radiative defect centers in the SiO2 matrix are responsible for the observed luminescence.


Item Type:Article
Additional Information:©1996 American Institute of Physics. (Received 10 October 1995; accepted 22 February 1996) The authors acknowledge F. W. Saris, G. N. van den Hoven, and R. P. Camata for fruitful discussions, and M. Easterbrook, J. Derks, and J. ter Beek for technical assistance. This work was supported by the U. S. Department of Energy, Basic Energy Sciences, and NATO Ministry for Scientific Affairs. The work at FOM was financially supported by NWO, STW, and IOP Electro-Optics.
Subject Keywords:SILICON; SILICON OXIDES; ION IMPLANTATION; COMPOSITE MATERIALS; PHOTOLUMINESCENCE; CONFINEMENT; EXCITONS; CRYSTAL DEFECTS; CARRIER LIFETIME; RECOMBINATION
Record Number:CaltechAUTHORS:MINapl96a
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:MINapl96a
Alternative URL:http://dx.doi.org/10.1063/1.115838
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2485
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:05 Apr 2006
Last Modified:26 Dec 2012 08:49

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