High quality multifold Ge/Si/Ge composite quantum dots for thermoelectric materials

We present an effective approach to grow high-quality thin film of composite quantum dots (CQDs) as a building block for thermoelectric materials, in which 3 times the usual Ge deposition can be incorporated within a 3-fold CQD. Selective chemical etching experiments reveal that a thin Si inserted l...

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Veröffentlicht in:Applied physics letters 2013-03, Vol.102 (10)
Hauptverfasser: Chang, Hung-Tai, Wang, Ching-Chi, Hsu, Jung-Chao, Hung, Ming-Tsung, Li, Pei-Wen, Lee, Sheng-Wei
Format: Artikel
Sprache:eng
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Zusammenfassung:We present an effective approach to grow high-quality thin film of composite quantum dots (CQDs) as a building block for thermoelectric materials, in which 3 times the usual Ge deposition can be incorporated within a 3-fold CQD. Selective chemical etching experiments reveal that a thin Si inserted layer in the CQDs modifies the growth mechanism through surface-mediated diffusion and SiGe alloying. Such thin-film-like CQD materials are demonstrated to exhibit reduced thermal conductivity κ⊥ with respect to the conventional QDs, perhaps as a consequence of enhanced diffusive phonon scattering from the high Si/Ge interface density and enhanced local alloying effect.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4794943