Nanoscale heat transfer at contact between a hot tip and a substrate

TL;DR

This paper analyzes heat transfer mechanisms at the nanoscale contact between a hot tip and a substrate, combining experimental data and modeling to understand conduction modes and resolution limits in ambient air.

Contribution

It provides a comprehensive analysis of solid-solid, gas, and water meniscus conduction modes and their impact on thermal contact conductance and microscope resolution.

Findings

All three heat transfer modes contribute similarly to conductance.

Contact radii range from 30 nm to 1 micron for different modes.

Scanning thermal microscopes have a 1-3 microns resolution in ambient air.

Abstract

Hot tips are used either for characterizing nanostructures by using scanning thermal microscopes or for local heating to assist data writing. The tip-sample thermal interaction involves conduction at solid-solid contact as well as conduction through the ambient gas and through the water meniscus. We analyze those three heat transfer modes with experimental data and modeling. We conclude that the three modes contribute in a similar manner to the thermal contact conductance but they have distinct contact radii ranging from 30 nm to 1 micron. We also show that any scanning thermal microscope has a 1-3 microns resolution when used in ambient air.