Reduction of the thermal conductivity in free-standing silicon nano-membranes investigated by non-invasive Raman thermometry
E. Chávez-Ángel,
J. S. Reparaz,
J. Gomis-Bresco,
M. R. Wagner,
J. Cuffe,
B. Graczykowski,
A. Shchepetov,
H. Jiang,
M. Prunnila,
J. Ahopelto,
F. Alzina,
C. M. Sotomayor Torres
Affiliations
E. Chávez-Ángel
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
J. S. Reparaz
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
J. Gomis-Bresco
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
M. R. Wagner
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
J. Cuffe
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
B. Graczykowski
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
A. Shchepetov
VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
H. Jiang
NanoMaterials Group, Department of Applied Physics and Center for New Materials, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto, Finland
M. Prunnila
VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
J. Ahopelto
VTT Technical Research Centre of Finland, PO Box 1000, 02044 VTT, Espoo, Finland
F. Alzina
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
C. M. Sotomayor Torres
ICN2 – Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona, Spain
We report on the reduction of the thermal conductivity in ultra-thin suspended Si membranes with high crystalline quality. A series of membranes with thicknesses ranging from 9 nm to 1.5 μm was investigated using Raman thermometry, a novel contactless technique for thermal conductivity determination. A systematic decrease in the thermal conductivity was observed as reducing the thickness, which is explained using the Fuchs-Sondheimer model through the influence of phonon boundary scattering at the surfaces. The thermal conductivity of the thinnest membrane with d = 9 nm resulted in (9 ± 2) W/mK, thus approaching the amorphous limit but still maintaining a high crystalline quality.
