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Surface-related states in oxidized silicon nanocrystals enhance carrier relaxation and inhibit Auger recombination

Othonos, Andreas and Lioudakis, Emmanouil and Nassiopoulou, A. G. (2008) Surface-related states in oxidized silicon nanocrystals enhance carrier relaxation and inhibit Auger recombination. NANOSCALE RESEARCH LETTERS, 3 (9). pp. 315-320. ISSN 1931-7573 (Print) 1556-276X (Online)

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Official URL: http://springerlink.com/content/26147740p20485k7/#...

Abstract

We have studied ultrafast carrier dynamics in oxidized silicon nanocrystals (NCs) and the role that surface-related states play in the various relaxation mechanisms over a broad range of photon excitation energy corresponding to energy levels below and above the direct bandgap of the formed NCs. Transient photoinduced absorption techniques have been employed to investigate the effects of surface-related states on the relaxation dynamics of photogenerated carriers in 2.8 nm oxidized silicon NCs. Independent of the excitation photon energy, non-degenerate measurements reveal several distinct relaxation regions corresponding to relaxation of photoexcited carriers from the initial excited states, the lowest indirect states and the surface-related states. Furthermore, degenerate and non-degenerate measurements at difference excitation fluences reveal a linear dependence of the maximum of the photoinduced absorption (PA) signal and an identical decay, suggesting that Auger recombination does not play a significant role in these nanostructures even for fluence generating up to 20 carriers/NC.

Item Type:Article
Uncontrolled Keywords:silicon nanocrystals; carrier dynamics; ultrafast spectroscopy; surface-related states; Auger recombination
Subjects:Material Science > Nanostructured materials
Physical Science > Photonics
ID Code:1924
Deposited By:Farnush Anwar
Deposited On:23 Dec 2008 11:39
Last Modified:23 Dec 2008 11:39

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