Measurement of thermal conductance of silicon nanowires at low temperature

TL;DR

This study measures the thermal conductance of individual silicon nanowires at low temperatures, revealing temperature-dependent behavior and deviations due to geometric effects, advancing understanding of phonon transport in nanoscale structures.

Contribution

It provides experimental data on silicon nanowire thermal conductance at low temperatures, highlighting the influence of geometry on phonon transport.

Findings

Conductance follows T^3 behavior above 1.3K

Deviation from T^3 at lowest temperatures due to geometry

Cross-section approaches phonon wavelength at 1K

Abstract

We have performed thermal conductance measurements on individual single crystalline silicon suspended nanowires. The nanowires (130 nm thick and 200 nm wide) are fabricated by e-beam lithography and suspended between two separated pads on Silicon On Insulator (SOI) substrate. We measure the thermal conductance of the phonon wave guide by the 3 method. The cross-section of the nanowire approaches the dominant phonon wavelength in silicon which is of the order of 100 nm at 1K. Above 1.3K the conductance behaves as T3, but a deviation is measured at the lowest temperature which can be attributed to the reduced geometry.