title: Hot-electron nanoscopy using adiabatic compression of surface plasmons.
abstract: Surface plasmon polaritons are a central concept in nanoplasmonics and have been exploited to develop ultrasensitive chemical detection platforms, as well as imaging and spectroscopic techniques at the nanoscale. Surface plasmons can decay to form highly energetic (or hot) electrons in a process that is usually thought to be parasitic for applications, because it limits the lifetime and propagation length of surface plasmons and therefore has an adverse influence on the functionality of nanoplasmonic devices. Recently, however, it has been shown that hot electrons produced by surface plasmon decay can be harnessed to produce useful work in photodetection, catalysis and solar energy conversion. Nevertheless, the surface-plasmon-to-hot-electron conversion efficiency has been below 1% in all cases. Here we show that adiabatic focusing of surface plasmons on a Schottky diode-terminated tapered tip of nanoscale dimensions allows for a plasmon-to-hot-electron conversion efficiency of ∼30%. We further demonstrate that, with such high efficiency, hot electrons can be used for a new nanoscopy technique based on an atomic force microscopy set-up. We show that this hot-electron nanoscopy preserves the chemical sensitivity of the scanned surface and has a spatial resolution below 50 nm, with margins for improvement.
authors.affiliation: 1] Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy [2] King Abdullah University of Science and Technology, PSE and BESE Divisions, Thuwal, 23955-6900, Kingdom of Saudi Arabia.
authors.forename: A
authors.initials: A
authors.lastname: Giugni
authors.forename: B
authors.initials: B
authors.lastname: Torre
authors.forename: A
authors.initials: A
authors.lastname: Toma
authors.forename: M
authors.initials: M
authors.lastname: Francardi
authors.forename: M
authors.initials: M
authors.lastname: Malerba
authors.forename: A
authors.initials: A
authors.lastname: Alabastri
authors.forename: R
authors.initials: R
authors.lastname: Proietti Zaccaria
authors.forename: M I
authors.initials: MI
authors.lastname: Stockman
authors.forename: E
authors.initials: E
authors.lastname: Di Fabrizio