Si and Ge nanocluster formation in silica matrix
- University of Rostock, Institute of Physics (Germany)
- Cornell University, School of Applied and Engineering Physics (United States)
- Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)
- Institute of Ion Beam Physics and Materials Research, Research Center Rossendorf (Germany)
High resolution transmission electron microscopy, scanning transmission electron microscopy, and cathodoluminescence have been used to investigate Si and Ge cluster formation in amorphous silicon-dioxide layers. Commonly, cathodoluminescence emission spectra of pure SiO{sub 2} are identified with particular defect centers within the atomic network of silica including the nonbridging oxygen hole center associated with the red luminescence at 650 nm (1.9 eV) and the oxygen deficient centers with the blue (460 nm; 2.7 eV) and ultraviolet band (295 nm; 4.2 eV). In Ge{sup +} ion-implanted SiO{sub 2}, an additional violet emission band appears at 410 nm (3.1 eV). The strong increase of this violet luminescence after thermal annealing is associated with formation of low-dimension Ge aggregates such as dimers, trimers, and higher formations, further growing to Ge nanoclusters. On the other hand, pure silica layers were modified by heavy electron beam irradiation (5 keV; 2.7 A/cm{sup 2}), leading to electronic as well as thermal dissociation of oxygen and the appearance of under-stoichiometric SiO{sub x}. This SiO{sub x} will undergo a phase separation and we observe Si cluster formation with a most probable cluster diameter of 4 nm. Such largely extended Si clusters will diminish the SiO{sub 2}-related luminescence and Si-crystal-related luminescence in the near IR.
- OSTI ID:
- 21088092
- Journal Information:
- Semiconductors, Vol. 41, Issue 4; Other Information: DOI: 10.1134/S1063782607040033; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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