Dresden 2014 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures

O 37.24: Poster

Dienstag, 1. April 2014, 18:30–22:00, P2

Surface plasmon enhanced chemiluminescence at metal surfaces using internal photodetection — Ulrich Hagemann, Felix Becker, and •Hermann Nienhaus — Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, D-47048 Duisburg, Germany

Light emission during reactions on metal surfaces is generally quenched. If detectable at all the photon yield is low. The study presents data from two model reactions at low temperatures, i.e., the oxidation of Mg and the chlorination of K surfaces [1]. The metals are prepared as thin layers on a rough 5 - 200 nm Ag film grown on p-Si(111) surfaces. The Ag/Si(111) contact is used as a Schottky photodiode allowing an internal 2π detection of the chemiluminescence photons. The photoyield can be enhanced up to an order of magnitude by varying the Ag film thickness. For Ag films in the thickness range between 30 and 50 nm, the yield shows characteristic maxima. The results can be explained by surface plasmon polaritons (SPP) in the Ag layer which are excited by the non-adiabatic chemical reaction on the Mg or K surface. The SPP decays radiatively into Si inducing the photocurrent. Model calculations are able to reproduce the observed yield maxima at certain Ag film thicknesses.

[1] F. Becker et al., JCP 138 (2013) 034710.