Rights statement: This is an author-created, un-copyedited version of an article accepted for publication/published in Nanotechnology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.1088/1361-6528/aa9497
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Thermal transport in epitaxial Si1-xGex alloy nanowires with varying composition and morphology
AU - Sachat, Alexandros
AU - Reparaz, J
AU - Spiece, Jean
AU - Alonso, M
AU - Goni, A
AU - Vaccaro, P
AU - Wagner, M
AU - Kolosov, Oleg Victor
AU - Torres, C
AU - Alzina, F
PY - 2017/11/21
Y1 - 2017/11/21
N2 - We report on structural, compositional, and thermal characterization of self-assembled in-plane epitaxial Si1-xGex alloy nanowires grown by molecular beam epitaxy on Si (001) substrates. The thermal properties were studied by means of scanning thermal microscopy, while the microstructural characteristics, the spatial distribution of the elemental composition of the alloy nanowires and the sample surface were investigated by transmission electron microscopy and energy dispersive x-ray microanalysis. We provide new insights regarding the morphology of the in-plane nanostructures, their size-dependent gradient chemical composition, and the formation of a 5 nm thick wetting layer on the Si substrate surface. In addition, we directly probe heat transfer between a heated scanning probe sensor and Si1-xGex alloy nanowires of different morphological characteristics and we quantify their thermal resistance variations. We correlate the variations of the thermal signal to the dependence of the heat spreading with the cross-sectional geometry of the nanowires using finite element method simulations. With this method we determine the thermal conductivity of the nanowires with values in the range of 2-3 Wm-1K-1. These results provide valuable information in growth processes and show the great capability of the scanning thermal microscopy technique in ambient environment for nanoscale thermal studies, otherwise not possible using conventional tech-niques.
AB - We report on structural, compositional, and thermal characterization of self-assembled in-plane epitaxial Si1-xGex alloy nanowires grown by molecular beam epitaxy on Si (001) substrates. The thermal properties were studied by means of scanning thermal microscopy, while the microstructural characteristics, the spatial distribution of the elemental composition of the alloy nanowires and the sample surface were investigated by transmission electron microscopy and energy dispersive x-ray microanalysis. We provide new insights regarding the morphology of the in-plane nanostructures, their size-dependent gradient chemical composition, and the formation of a 5 nm thick wetting layer on the Si substrate surface. In addition, we directly probe heat transfer between a heated scanning probe sensor and Si1-xGex alloy nanowires of different morphological characteristics and we quantify their thermal resistance variations. We correlate the variations of the thermal signal to the dependence of the heat spreading with the cross-sectional geometry of the nanowires using finite element method simulations. With this method we determine the thermal conductivity of the nanowires with values in the range of 2-3 Wm-1K-1. These results provide valuable information in growth processes and show the great capability of the scanning thermal microscopy technique in ambient environment for nanoscale thermal studies, otherwise not possible using conventional tech-niques.
KW - SThM
KW - scanning thermal
KW - nanowires
KW - nanoscale thermal transport
U2 - 10.1088/1361-6528/aa9497
DO - 10.1088/1361-6528/aa9497
M3 - Journal article
VL - 28
JO - Nanotechnology
JF - Nanotechnology
SN - 0957-4484
IS - 50
M1 - 505704
ER -