Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 11: Ultrafast and Nonlinear Plasmonics

O 11.12: Vortrag

Montag, 16. März 2015, 17:45–18:00, MA 004

Electron tunneling mediated amplification of radiative plasmon decay — •xiao wang, kai braun, dai zhang, heiko peisert, hilamar adler, thomas chassé, and alfred meixner — Institute of physical and theoretical chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany

Here we demonstrate electron tunneling mediated amplification of photoluminescence (PL) from an Au-Au junction in a combined tip enhanced near-field optical and scanning tunneling microscope. Luminescence spectra were collected from the same Au-Au junction with different bias voltages with and without laser illumination. Without optical excitation the luminescence spectra show typical plasmon modes in the spectral range from 700-1050 nm excited by inelastic electron tunneling. Under laser illumination at 634 nm, at low bias voltages the PL is dominated by the radiative decay of the laser excited electron-hole pairs from the sp/d interband transition with a single band at 690 nm. At higher bias voltages, the luminescence increases dramatically, showing both the band from electron-hole recombination and the plasmon-modes from inelastic tunneling. The increase of the luminescence from inelastic tunneling is more than an order of magnitude and is attributed to the laser induced hot-electron population closely above the Fermi-level to inelastic tunneling having a higher radiative decay rate than the conducting electrons from the sp-band.