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

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 is converted to heat via inelastic scattering while traversing a solid‐state medium and the generated heat often complicates experimental analysis. A nanocalorimeter enables capturing heat generation induced by electron beams, and in parallel, the electron energy loss spectroscopy measurements reveal that a key energy conversion is to be responsible for the electrons in an outer shell.