Automated plasmon peak fitting derived temperature mapping in a scanning transmission electron microscope

Anthony Barker,Robert Klie,Juan Pablo Oviedo,Bibash Sapkota

doi:10.1063/5.0039864

Abstract

Nanoscale thermometry, an approach based on non-invasive, yet precise measurements of temperature with nanometer spatial resolution, has emerged as a very active field of research over the last few years. In transmission electron microscopy, nanoscale thermometry is particularly important during in situ experiments or to assess the effects of beam induced heating. In this article, we present a nanoscale thermometry approach based on electron energy-loss spectroscopy in a transmission electron microscope to measure locally the temperature of silicon nanoparticles using the energy shift of the plasmon resonance peak with respect to the zero-loss peak as a function of temperature. We demonstrate that using non-negative matrix factorization and curve fitting of stacked spectra, the temperature accuracy can be improved significantly over previously reported manual fitting approaches. We will discuss the necessary acquisition parameters to achieve a precision of 6 meV to determine the plasmon peak position.

Highlights

Where T is the temperature, his the reduced Planck’s constant, n(T) is the temperature dependent valence electron density, e is the electron charge, m is the electron mass, and ε0 is the vacuum permittivity
The experimental data were acquired using a JEOL ARM200CF equipped with a cold-field emission source and a Gatan Continuum GIF spectrometer, providing an energy resolution of better than 350 meV, as measured by the full-width at half maximum of the zero-loss peak
The Si samples were prepared by crushing a Si wafer drop-cast onto a previously calibrated Protochips heating echip as scitation.org/journal/adv well as the Protochips Aduro double tilt holder to perform the in situ heating experiments

Summary

Introduction

Where T is the temperature, his the reduced Planck’s constant, n(T) is the temperature dependent valence electron density, e is the electron charge, m is the electron mass, and ε0 is the vacuum permittivity. The experimental data were acquired using a JEOL ARM200CF equipped with a cold-field emission source and a Gatan Continuum GIF spectrometer, providing an energy resolution of better than 350 meV, as measured by the full-width at half maximum of the zero-loss peak.

Results

Conclusion