Temperature and structure size dependence of the thermal conductivity of porous silicon

¹ Max Planck Institute of Microstructure Physics - Weinberg 2, 06120 Halle, Germany, EU
² Institute for Material Science, University of Kiel - Kaiserstr. 2, 24143 Kiel, Germany, EU

^a deboor@mpi-halle.de

Received: 6 May 2011
Accepted: 9 August 2011

Abstract

In order to assess the potential of porous Si as thermoelectric material we have performed thermal conductivity measurements in dependence of both temperature and average structure size. Investigations on samples with average structure sizes between 7 nm and 100 nm reveal a pronounced reduction in thermal conductivity which is encouraging for the future use of porous Si as thermoelectric material. The observed dependence on structure size and temperature can be explained in terms of a simple kinetic model based on the reduction of the effective phonon mean free path.