Direct observation of hot-electron-enhanced thermoelectric effects in silicon nanodevices

The study of thermoelectric behaviors in miniaturized transistors is critical for on-chip thermal management. Using nanothermometric imaging of both electron temperature (Te) and lattice temperature (Tl) in a silicon nanoconstriction, this work directly visualizes prominent thermoelectric effects near electron hotspots. When current passes through the constriction, electron hotspots with Te ~1500 K far exceed Tl ~320 K, producing an extremely large electron-temperature gradient (~1 K/nm) that yields strong thermoelectric signatures. Quantitative measurements show a distinctive third-power dependence of the thermoelectric signal on electrical current, consistent with theoretically predicted nonequilibrium thermoelectric effects where the Peltier coefficient depends on Te. The results indicate that nonequilibrium hot carriers can enhance thermoelectric performance, offering new opportunities for nanoscale thermal management in post-Moore electronics.