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Proceedings Paper

Structural transformations in self-assembled semiconductor quantum dots as inferred by transmission electron microscopy
Author(s): Peter Mock; Yuanyuan Lei; Teya Topuria; Nigel D. Browning; Regina Ragan; Kyu S. Min; Harry A. Atwater
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Paper Abstract

Transmission electron microscopy studies in both the scanning and parallel illumination mode on samples of two generic types of self-assembled semiconductor quantum dots are reported. III-V and II-VI quantum dots as grown in the Stranski-Krastanow mode are typically alloyed and compressively strained to a few %, possess a more or less random distribution of the cations and/or anions over their respective sublattices, and have a spatially non-uniform chemical composition distribution. Sn quantum dots in Si as grown by temperature and growth rate modulated molecular beam epitaxy by means of two mechanisms possess the diamond structure and are compressively strained to the order of magnitude 10 %. These lattice mismatch strains are believed to trigger atomic rearrangements inside quantum dots of both generic types when they are stored at room temperature over time periods of a few years. The atomic rearrangements seem to result in long-range atomic order, phase separation, or phase transformations. While the results suggest that some semiconductor quantum dots may be structurally unstable and that devices based on them may fail over time, triggering and controlling structural transformations in self-assembled semiconductor quantum dots may also offer an opportunity of creating atomic arrangements that nature does not otherwise provide.

Paper Details

Date Published: 15 November 2002
PDF: 12 pages
Proc. SPIE 4807, Physical Chemistry of Interfaces and Nanomaterials, (15 November 2002); doi: 10.1117/12.450998
Show Author Affiliations
Peter Mock, Univ. of Illinois/Chicago (United States)
Yuanyuan Lei, Univ. of Illinois/Chicago (United States)
Teya Topuria, Univ. of Illinois/Chicago (United States)
Nigel D. Browning, Univ. of Illinois/Chicago (United States)
Regina Ragan, California Institute of Technology (United States)
Kyu S. Min, California Institute of Technology (United States)
Harry A. Atwater, California Institute of Technology (United States)


Published in SPIE Proceedings Vol. 4807:
Physical Chemistry of Interfaces and Nanomaterials
Jin Z. Zhang; Zhong L. Wang, Editor(s)

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