Scanning Thermal Microscopy in Air and Vacuum: A Comparison

TL;DR

This study compares scanning thermal microscopy in air and vacuum, revealing significant differences in signal strength, stability, and resolution, and highlights the impact of environmental conditions on heat transfer mechanisms.

Contribution

It provides a detailed comparison of thermal microscopy signals and resolution in air versus vacuum, elucidating the effects of ambient conditions on measurement accuracy.

Findings

Signals in air are 2.5 to 40 times larger than in vacuum.

Air measurements are more stable over time.

Edge resolution is approximately 39% better in vacuum.

Abstract

We present measurements comparing scanning thermal microscopy in air and vacuum. Signal levels are compared and resolution is probed by scanning over the edge of a nanofabricated Ag square embedded in SiO2. Signals measured in air were seen to be 2.5 to 40 times larger than in vacuum. Furthermore, the air signals were stable while the vacuum signals varied significantly. Edge widths measured in air were approximately 39 % larger than those measured in vacuum. Our observations are consistent with the air measurements experiencing heat transfer from the surrounding sample via conduction and convection as well as the formation of a water-related meniscus at the tip-sample junction. These results contribute to the understanding of the complex heat exchange effects that can occur in scanning thermal microscopy when it is conducted in an ambient atmosphere.