Nonradiative Plasmon Decay and Hot Carrier Dynamics: Effects of Phonons, Surfaces, and Geometry

Abstract

The behavior of metals across a broad frequency range from microwave to ultraviolet frequencies is of interest in plasmonics, nanophotonics, and metamaterials. Depending on the frequency, losses of collective excitations in metals can be predominantly classical resistive effects or Landau damping. In this context, we present first-principles calculations that capture all of the significant microscopic mechanisms underlying surface plasmon decay and predict the initial excited carrier distributions so generated. Specifically, we include ab initio predictions of phonon-assisted optical excitations in metals, which are critical to bridging the frequency range between resistive losses at low frequencies and direct interband transitions at high frequencies. In the commonly used plasmonic materials, gold, silver, copper, and aluminum, we find that resistive losses compete with phonon-assisted carrier generation below the interband threshold, but hot carrier generation via direct transitions dominates above threshold. Finally, we predict energy-dependent lifetimes and mean free paths of hot carriers, accounting for electron-electron and electron-phonon scattering, to provide insight toward transport of plasmonically generated carriers at the nanoscale.

Planar Hot-Electron Photodetection with Tamm Plasmons

“…47 Following the same procedures, when introducing other materials, the measured frequency-dependent dielectric constant can be used in RCWA and FEM. Taking into account the resistive loss (P resistive ~30%) of the absorbed energy, which is dissipated without hot electrons generation due to the intrinsic lifetime of the electronic states comprising the collective oscillation, 44 the spatially dependent hot-electron generation rate (G) can be written as:…”

“…44 With the initial energy distribution D(E) of hot electrons, the spatial distributions of the hot electron generation rate G(x, z), and the energy-dependent transport probability P 1 (x, z, E), the flux of hot electrons reaching the top or the bottom M/S interface in the TP-based HE PDs can be written as:…”

“…Moreover, Figure 1c shows that the special design of MSM+DBR allows an extremely low reflection dip by the device (device transmittance is zero with the presence of the rear Au reflector), affirming a greatly strengthened TP. It is noticed that the thickness of the top Au layer (i.e., adjacent to the DBR) is much smaller than the mean free path (MFP) of electrons in Au (~ 40 nm for low-energy electrons) 44 to ensure a high probability for the generated hot electrons to reach the M/S interface before thermalization and finally accomplish the interfacial electron transfer process. 15 Besides, it is crucial that TiO 2 (i.e., the high-index layer) has to be the layer adjacent to the MSM to ensure the excitation of TPs.…”

Hot‐Electron‐Mediated Photochemical Reactions: Principles, Recent Advances, and Challenges

“…a-d) Reproduced with permission. [27] Copyright 2016, American Chemical Society. e) The momentum and energy distribution of hot carriers with diffusion lengths in gold, calculated using the simplified Boltzmann equation.…”

Harvesting the loss: surface plasmon-based hot electron photodetection

“…In fact, in this regime, none of the commonly used plasmonic materials, including gold, silver, aluminum, and copper, exhibit the isotropic momentum distribution assumed in Fowler's theory [32]. Additionally, the effects of phonons and surfaces on hot carriers have also been studied [79].…”