AVS 56th International Symposium & Exhibition
    Nanometer-scale Science and Technology Wednesday Sessions
       Session NS-WeM

Paper NS-WeM3
Plasmon Induced Molecular Conductivity in Devices

Wednesday, November 11, 2009, 8:40 am, Room L

Session: Nanoscale Devices and Sensors and Welch Award
Presenter: D.A. Bonnell, University of Pennsylvania
Authors: P. Banerjee, University of Maryland
D. Conklin, University of Pennsylvania
S.U. Nanayakkara, University of Pennsylvania
T.-H. Park, University of Michigan
M.J. Therien, Duke University
D.A. Bonnell, University of Pennsylvania
Correspondent: Click to Email
Plasmonics and molecular electronics are two fields that explicitly exploit nanoscale physical phenomena. In the former, optical interactions with nanosized particles induce surface plasmons creating locally intense electric fields. In the latter, two decades of intense research has focused on electrical conduction in organic molecules to enable molecular electronics. The interaction of plasmons and electrical conduction has not been observed. Here we demonstrate the ability of a plasmon to alter the electrical properties of a molecular junction. Arrays of Au nanoparticles with different separations are assembled on an insulating substrate and functionalized with porphyrin compounds. These molecules posses unique optical properties and electron delocalization lengths on the order of 7-8nm. The wavelength and temperature dependence of transport in these hybrid devices reveal differences on photo conduction mechanism with wavelength. Three mechanisms are identified, one that operates in the dark current, one associated with electron-hole generation on absorption and one induced by surface plasmons. This ability of plasmons to directly influence electrical conductivity is a new mechanism of photoconduction that suggests a variety of optoelectronic applications.