Hot Electron Emission in Plasmonic Thermionic Converters
Published in ACS Energy Letters, 2019
Authors: Shengxiang Wu, Nicki Hogan, and Matthew Sheldon $^\dagger$
In this paper, we discovered a bi-exponential decay of anti-Stokes Raman signal from plasmonic (e.g. gold) nanostructures fabricated through electron beam lithography. Inspired by the pioneering works of anti-Stokes Raman thermometry developed on plasmonic nanoparticles, we attributed the two slopes (if plotted in logrithmic scale) to two electronic temperatures - most of the electrons are thermalized in equilibrium with lattice phonons with temperature $T_l$, while the continuous optical pumping maintained a small fraction of electrons at higher electronic temperature $T_e$ even under steady-state illumination. Furthermore, we constrcuted a thermionic emission device that electrically attested the existance of hot electrons at ~ 2,000 K.