Atomistic Theory of Hot-Carrier Generation in Aluminum Nanoparticles

Hot electrons and holes generated from the decay of localized surface plasmons (LSPs) in aluminum nanostructures have significant potential for applications in photocatalysis, photodetection, and other optoelectronic devices. Here, we present a theoretical study of hot-carrier generation in aluminum nanospheres using a recently developed modeling approach that combines a solution of the macroscopic Maxwell equation with large-scale atomistic tight-binding simulations. Different from standard plasmonic metals, such as gold or silver, we find that the energetic distribution of hot electrons and holes in aluminum nanoparticles is almost constant for all allowed energies. Only at relatively high photon energies, a reduction of the generation rate of highly energetic holes and electrons close to the Fermi level is observed, which is attributed to band structure effects suppressing interband decay channels. We also investigate the dependence of hot-carrier properties on the nanoparticle diameter and the environmental dielectric constant. The insights from our study can inform experimental efforts toward highly efficient aluminum-based hot-carrier devices.