Measurement of anisotropic thermal conductivity of a dense forest of nanowires using the 3ω method

Dhruv Singhal (1, 2) , Jessy Paterson (1) , Dimitri Tainoff (1) , Jacques Richard (1) , Meriam Ben Khedim (1) , Pascal Gentile (3, 2) , Laurent Cagnon (4) , Daniel Bourgault (1) , Denis Buttard (2) , Olivier Bourgeois (1)

1 NEEL - TPS - Thermodynamique et biophysique des petits systèmes
2 SiNaps - Silicon Nanoelectronics Photonics and Structures
3 SP2M - UMR 9002 - Service de Physique des Matériaux et Microstructures
4 NEEL - MNM - Micro et NanoMagnétisme

The 3ω method is a dynamic measurement technique developed for determining the thermal conductivity of thin films or semi-infinite bulk materials. A simplified model is often applied to deduce the thermal conductivity from the slope of the real part of the ac temperature amplitude as a function of the logarithm of frequency, which in-turn brings a limitation on the kind of samples under observation. In this work, we have measured the thermal conductivity of a forest of nanowires embedded in nanoporous alumina membranes using the 3ω method. An analytical solution of 2D heat conduction is then used to model the multilayer system, considering the anisotropic thermal properties of the different layers, substrate thermal conductivity and their thicknesses. Data treatment is performed by fitting the experimental results with the 2D model on two different sets of nanowires (silicon and BiSbTe) embedded in the matrix of nanoporous alumina template, having thermal conductivities that differ by at least one order of magnitude. These experimental results show that this method extends the applicability of the 3ω technique to more complex systems having anisotropic thermal properties.

Mots clés: thermal conductivity; Nanowire NW; 3 omega method

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Dhruv Singhal, Jessy Paterson, Dimitri Tainoff, Jacques Richard, Meriam Ben Khedim, et al.. Measurement of anisotropic thermal conductivity of a dense forest of nanowires using the 3ω method. Review of Scientific Instruments, 2018, 89 (8), pp.084902. ⟨10.1063/1.5025319⟩. ⟨hal-01910641⟩