Secondary electron emission current mapping for nanoscale thermometry

Secondary electron (SE) emission is temperature-dependent, and thus could form the basis of an electron microscopy-based thermometry technique with nanoscale spatial resolution. To explore this possibility, we measure the SE emission from heated test structures using scanning transmission electron microscopy electron beam-induced current (STEM EBIC) imaging. The test structures consist of an electrode, which is made of platinum or amorphous carbon, and an encircling heater. Aluminium nanoparticles decorate the test structures and serve as local nanothermometers that we read-out with plasmon energy expansion themometry (PEET). Energizing the heaters, we measure the SE emission from the electrodes and nanothermometers. The SE emission from Pt, C, and Al is a simple, supralinear function of the PEET-calibrated temperature that is well-fit with a single free parameter. SEEBIC thermometry thus shows promise for being a widely applicable, TEM-based temperature mapping technique.