Fabrication of Bi2Te3 nanowire arrays and thermal conductivity measurement by 3ω-scanning thermal microscopy

M. Muñoz Rojo (1) , Stéphane Grauby (2) , Jean-Michel Rampnoux (2) , O. Caballero-Calero (1) , M. Martin-Gonzalez (1) , Stefan Dilhaire (2)

1 IMM - Instituto de Microelectronica de Madrid
2 LOMA - Laboratoire Ondes et Matière d'Aquitaine

Bi2Te3 is well-known for its utility in thermoelectrical applications and more recently as topological insulator. Its nanostructuration has attracted plenty of attention because of its potential capacity to reduce thermal conductivity. Here, we have grown a composite sample made of a Bi2Te3 nanowires (NWs) array embedded in an alumina matrix. We have then performed scanning thermal microscopy (SThM) in a 3ω configuration to measure its equivalent thermal resistance. Using an effective medium model, we could then estimate the mean composite thermal conductivity as well as the thermal conductivity of the NWs to be, respectively, (λC) = (1.68 +/- 0.20) W/mK and (λNW) = (1.37 +/- 0.20) W/mK, showing a slight thermal conductivity reduction. Up to now, there have been two main techniques reported in literature to evaluate the thermal conductivity of nanostructures: the use of a thermal microchip to probe a single NW once its matrix has been dissolved or the probing of the whole NWs array embedded in a matrix, obtaining the thermal conductivity of the whole as an effective medium. However, the 3ω-SThM presented here is the only technique able to measure the thermal conductivity of single NWs embedded in a matrix as well as the thermal conductivity of the composite locally. This technique is more versatile and straightforward than other methods to obtain the thermal conductivity of nanostructures.

Mots clés: alumina; bismuth compounds; nanocomposites; nanofabrication; nanowires; thermal conductivity; thermal resistance; topological insulators; Methods of nanofabrication and processing; Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves

Domaines: Thermique [physics.class-ph]

M. Muñoz Rojo, Stéphane Grauby, Jean-Michel Rampnoux, O. Caballero-Calero, M. Martin-Gonzalez, et al.. Fabrication of Bi2Te3 nanowire arrays and thermal conductivity measurement by 3ω-scanning thermal microscopy. Journal of Applied Physics, 2013, 113 (5), pp.054308 (1-7). ⟨10.1063/1.4790363⟩. ⟨hal-00805572⟩