DocumentCode :
649525
Title :
Nanoscale thermal transport and phonon dynamics in ultra-thin Si based nanostructures
Author :
Wagner, M.R. ; Chavez-Angel, E. ; Gomis-Bresco, J. ; Reparaz, J.S. ; Shchepetov, A. ; Prunnila, Mika ; Ahopelto, Jouni ; Alzina, F. ; Sotomayor-Torres, C.M.
Author_Institution :
Catalan Inst. of Nanotechnol. (ICN), Bellaterra, Spain
fYear :
2013
fDate :
25-27 Sept. 2013
Firstpage :
10
Lastpage :
12
Abstract :
We study the dynamics of acoustic phonons in ultra-thin free-standing silicon membranes both experimentally and theoretically. We discuss the impact of the lifetimes of the acoustic phonons on the thermal transport properties of the membranes with thicknesses ranging from 8 nm to 1.5 μm. The phonon lifetimes are determined by measuring the dynamic variation of the reflectivity using ultra-fast pump-probe spectroscopy. This is achieved by asynchronous optical sampling (ASOPS) of two actively coupled femto-second laser oscillators. The coherent acoustic phonon lifetime is obtained from the dynamical variations of the reflectivity with a sensitivity of 10-5 and a time resolution of about 50 fs. The experimental results are compared to theoretical calculations considering both intrinsic and extrinsic relaxation scattering processes.
Keywords :
high-speed optical techniques; membranes; nanostructured materials; phonons; reflectivity; silicon; thermal conductivity; Si; acoustic phonon dynamics; asynchronous optical sampling; coupled femtosecond laser oscillators; extrinsic relaxation scattering; intrinsic relaxation scattering; nanoscale thermal transport; reflectivity; size 8 nm to 1.5 mum; thermal conductivity; ultrafast pump-probe spectroscopy; ultrathin free-standing silicon membranes; ultrathin silicon nanostructures;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Thermal Investigations of ICs and Systems (THERMINIC), 2013 19th International Workshop on
Conference_Location :
Berlin
Print_ISBN :
978-1-4799-2271-0
Type :
conf
DOI :
10.1109/THERMINIC.2013.6675218
Filename :
6675218
Link To Document :
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