Thermal properties of SnSe nanoflakes by AFM-based Scanning Thermal Microscopy measurements

TL;DR

This study uses AFM-based scanning thermal microscopy to measure how the thermal resistance of SnSe nanoflakes varies with thickness, revealing diffusive heat transport governed by phonon mean free paths.

Contribution

It provides nanoscale thermal resistance measurements of SnSe nanoflakes across different thicknesses, elucidating heat transport mechanisms at the nanoscale.

Findings

Thermal resistance increases with nanoflake thickness.

Heat transport follows Fourier's law, indicating diffusive mechanisms.

Phonon mean free path in SnSe is approximately 5 nm at room temperature.

Abstract

We investigated the thermal resistance of SnSe nanoflakes using scanning thermal microscopy, an extension of atomic force microscopy that allows for nanoscale thermal mapping. The nanoflakes studied ranged in thickness from 5 nm to 40 nm, enabling us to observe the thermal properties across a wide range of dimensions. Our results show a clear trend: as the thickness of the nanoflakes increases, the thermal resistance also increases. This suggests that diffusive mechanisms govern heat transport in SnSe nanoflakes and follow Fourier's law of heat conduction. The observed behavior can be attributed to the inherently short phonon mean free path in SnSe which is on the order of 5 nm at room temperature.