Hot-electron dynamics in plasmonic nanostructures

Abstract

The coherent oscillations of mobile charge carriers near the surface of good conductors-surface plasmons-are been exploited in many applications in information technologies, clean energy, high-density data storage, photovoltaics, chemistry, biology, medicine and security. Light can be coupled to surface plasmons and trapped near the interface between a metal and an adjacent material. This leads to the nanoscale confinement of light, impossible by any other means, and a related electromagnetic field enhancement. Microscopic electron dynamic effects associated with surface plasmons are capable of significantly influencing physical and chemical processes near a conductor surface, not only as a result of the high electric fields, but also via the excitation of energetic charge carriers: holes below Fermi level or electrons above it. When remaining inside plasmonic media, these so-called hot carriers result in nonlinear, Kerr-type, optical effects important for controlling light with light. They can also transfer into the surroundings of the nanostructures, resulting in photocurrent, or they can interact with adjacent molecules and materials, inducing photochemical transformations. Understanding the dynamics of hot carriers and related effects in plasmonic nanostructures is essential for the development of ultrafast detectors and nonlinear optical components, broadband photocatalysis, enhanced nanoscale optoelectronic devices, nanoscale and ultrafast temperature control, and other technologies of tomorrow. This review will discuss the basics of plasmonically-engendered hot electrons, theoretical descriptions and experimental methods to study them, and describe prototypical processes and examples of the most promising applications of hot-electron processes at the metal interfaces.