Issue 7, 2014

Designer Ge/Si composite quantum dots with enhanced thermoelectric properties

Abstract

An otherwise random, self-assembly of Ge/Si composite quantum dots (CQDs) on Si was controlled by inserting a layer of Si, sub-dot stacks, and post-annealing to produce micron-scale-thick QD layers with desired QD morphology, interface density, and composition distribution. A heterostructure consisting of a deliberate insertion of Si between Ge sub-dots is shown to improve the epitaxial coherence of the Ge QDs by suppression of the Ge surface interdiffusion and coarsening. As compared to regular-QD materials, the thin-film-like multifold-CQD materials are found to exhibit both reduced cross-plane thermal conductivity and enhanced electrical conductivity, and 1.5 times higher ZT value by calculation, providing a promising building block for practical thermoelectric applications in micro- or nanoelectronics.

Graphical abstract: Designer Ge/Si composite quantum dots with enhanced thermoelectric properties

Supplementary files

Article information

Article type
Paper
Submitted
28 Nov 2013
Accepted
04 Jan 2014
First published
10 Jan 2014

Nanoscale, 2014,6, 3593-3598

Author version available

Designer Ge/Si composite quantum dots with enhanced thermoelectric properties

H. Chang, S. Wang and S. Lee, Nanoscale, 2014, 6, 3593 DOI: 10.1039/C3NR06335F

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