The role of quantum-confined excitons vs defects in the visible luminescence of SiO{sub 2} films containing Ge nanocrystals
- Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States)
- FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam (The Netherlands)
Synthesis of Ge nanocrystals in SiO{sub 2} films is carried out by precipitation from a supersaturated solid solution of Ge in SiO{sub 2} 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{sup +}-implanted samples and reversible PL quenching by hydrogen or deuterium suggest that radiative defect centers in the SiO{sub 2} matrix are responsible for the observed luminescence. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 283782
- Journal Information:
- Applied Physics Letters, Vol. 68, Issue 18; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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