Nanoscale temperature mapping through thermal vibration characterization using scanning precession electron diffraction

Accurate temperature measurement with a high spatial resolution is essential for understanding thermal behavior in integrated nanoscale devices and especially at heterogeneous interfaces. However, existing techniques are often limited by insufficient spatial resolution. Here, we showcase the direct and noncontact temperature measurement with a nanometer spatial resolution using transmission electron microscopy. The experimental probe is the combination of a scanning nanobeam with precession electron diffraction, which offers the collection of kinematic diffraction intensity from a local area at the nanometer scale. With a precalculated, sample- and geometry-specific structure factor-based correction, the linear fitting of diffraction intensities allows the determination of the Debye-Waller factor and, thus, temperature with a precision of 10^-4 square angstrom per °C. Using graphene as a model material, this work reveals the influence of sample tilt, lattice thermal expansion, and sample thickness on Debye-Waller factor and offers a route to improving the measurement precision along with spatial resolution. The approach establishes a broadly applicable strategy for nanoscale thermometry in low-dimensional and heterogeneous materials.