Direct Quantification of Heat Generation Due to Inelastic Scattering of Electrons Using a Nanocalorimeter

Abstract

Transmission electron microscopy (TEM) is arguably the most important tool for atomic‐scale material characterization. A significant portion of the energy of transmitted electrons is transferred to the material under study through inelastic scattering, causing inadvertent damage via ionization, radiolysis, and heating. In particular, heat generation complicates TEM observations as the local temperature can affect material properties. Here, the heat generation due to electron irradiation is quantified using both top‐down and bottom‐up approaches: direct temperature measurements using nanowatt calorimeters as well as the quantification of energy loss due to inelastic scattering events using electron energy loss spectroscopy. Combining both techniques, a microscopic model is developed for beam‐induced heating and to identify the primary electron‐to‐heat conversion mechanism to be associated with valence electrons. Building on these results, the model provides guidelines to estimate temperature rise for general materials with reasonable accuracy. This study extends the ability to quantify thermal impact on materials down to the atomic scale.

Electron Beam Induced Enhancement and Suppression of Oxidation in Cu Nanoparticles in Environmental Scanning Transmission Electron Microscopy

“…The electron beam-induced phenomena depend largely on the material under study but typically include sample heating, defect formation, phase transformation, charging, and ionization of the surrounding gases. Electron beam-induced changes in the local temperature are not trivial to quantify, and different approaches have been attempted to measure heat generation due to electron beam irradiation. − Sample charging, due to the ejection of secondary, core, and Augur electrons, is another effect, which cannot be neglected in in situ E­(S)­TEM studies of electrodes, electrocatalysts, and catalytic redox reactions. , In these cases, the electron beam-induced potential can be in the order of the redox potential of the desired reaction and thus needs to be carefully addressed. Electron beam-induced atomic displacement, known as the knock-on damage, causes the formation of interstitials and vacancies inside the sample and can lead to structural changes such as nanoparticle reorientation, re-crystallization, − enhancement of diffusional process, , and mechanical deformations .…”

Lattice Boltzmann method with effective correction of phonon properties for nano/microscale heat transfer

“…Over the last few decades, the characteristic length of electronic devices has shrunk significantly in order to improve their performance. Nevertheless, the self-heating effect generates tremendous heat, and is becoming one of the most important factors that restrict the in-depth reduction of the characteristic length [1][2][3][4][5]. In addition, the strong size effect and boundary effect at nano/microscale inhibit the transport capability of heat carriers.…”