Nanosecond nanothermometry in an electron microscope

TL;DR

This paper introduces a new pump-probe STEM technique combining laser heating and time-resolved EELS to measure temperature dynamics at nanometer and nanosecond scales, enabling detailed study of transient thermal phenomena.

Contribution

A novel method that achieves simultaneous high spatial and temporal resolution in nanothermometry within an electron microscope, advancing thermal analysis of nanostructures.

Findings

Successfully mapped temperature changes at nanometer and nanosecond scales.

Experimental data aligned with theoretical heat diffusion models.

Demonstrated applicability across various nanomaterials.

Abstract

Thermal transport in nanostructures plays a critical role in modern technologies. As devices shrink, techniques that can measure thermal properties at nanometer and nanosecond scales are increasingly needed to capture transient, out-of-equilibrium phenomena. We present a novel pump-probe photon-electron method within a scanning transmission electron microscope (STEM) to map temperature dynamics with unprecedented spatial and temporal resolutions. By combining focused laser-induced heating and synchronized time-resolved monochromated electron energy loss spectroscopy (EELS), we track phonon, exciton and plasmon signals in various materials, including silicon nitride, aluminum thin film, and transition metal dichalcogenides. Our results demonstrate the technique's ability to follow temperature changes at the nanometer and nanosecond scales. The experimental data closely matched theoretical heat diffusion models, confirming the method's validity. This approach opens new opportunities to investigate transient thermal phenomena in nanoscale materials, offering valuable insights for applications in thermoelectric devices and nanoelectronics.