STEM in situ thermal wave observations for investigating thermal diffusivity in nanoscale materials and devices.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38215197.
- Also identified by DOI 10.1126/sciadv.adj3825 and PMC identifier 10786416.
- Licence recorded as CC BY-NC.
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Abstract
Practical techniques to identify heat routes at the nanoscale are required for the thermal control of microelectronic, thermoelectric, and photonic devices. Nanoscale thermometry using various approaches has been extensively investigated, yet a reliable method has not been finalized. We developed an original technique using thermal waves induced by a pulsed convergent electron beam in a scanning transmission electron microscopy (STEM) mode at room temperature. By quantifying the relative phase delay at each irradiated position, we demonstrate the heat transport within various samples with a spatial resolution of ~10 nm and a temperature resolution of 0.01 K. Phonon-surface scatterings were quantitatively confirmed due to the suppression of thermal diffusivity. The phonon-grain boundary scatterings and ballistic phonon transport near the pulsed convergent electron beam were also visualized.