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

Paper NS-WeM6
Surface Plasmon Induced Enhancement of Hot Electron Flow Generated by Photons Probed with Metal-Semiconductor Nanodiodes

Wednesday, November 11, 2009, 9:40 am, Room L

Session: Nanoscale Devices and Sensors and Welch Award
Presenter: J.Y. Park, University of California, Berkeley and Lawrence Berkeley National Laboratory
Authors: J.Y. Park, University of California, Berkeley and Lawrence Berkeley National Laboratory
H.S. Lee, University of California, Berkeley and Lawrence Berkeley National Laboratory
J.R. Renzas, University of California, Berkeley and Lawrence Berkeley National Laboratory
R. Baker, University of California, Berkeley and Lawrence Berkeley National Laboratory
G.A. Somorjai, University of California, Berkeley and Lawrence Berkeley National Laboratory
Correspondent: Click to Email
We present hot electron generation from photon absorption on metal-semiconductor Schottky diodes and its amplification by localized surface plasmon resonance. Hot electron flow was generated on a gold thin film (< 10 nm) by photon absorption and directly measured as a form of photocurrent on chemically modified gold thin film metal-semiconductor (TiO2) Schottky diodes. The short-circuit photocurrent obtained with low energy photons (lower than the 3.1 eV bandgap of TiO2) is consistent with Fowler’s law, which confirms the presence of hot electron flow. The morphology of the metal thin film was modified to a connected gold island structure with a lateral length scale of 50- 100 nm after heating in oxygen. The nanometer scale domains in the gold island structures were electrically connected to the Ohmic pad, ensuring the measurement of the flow of hot electrons. These connected island structures exhibit a localized surface plasmon with peak energy at 550- 570 nm, which was separately characterized with UV-Vis. Hot electron flow (after normalizing photon absorption) was enhanced by a factor of three on the connected gold island structure. This result indicates correlation between the hot electron flow and localized surface plasmon resonance. Possible mechanisms for surface plasmon induced enhancement of hot electron generation are also discussed.