AVS 59th Annual International Symposium and Exhibition
    Surface Science Monday Sessions
       Session SS-MoM

Paper SS-MoM10
Analysis of Chemicurrent Components Induced by Hydrogen Oxidation on Pt/n-GaP and Pt/n-SiC Planar Schottky Nanostructures

Monday, October 29, 2012, 11:20 am, Room 21

Session: Nonequillibrium and Nonlinear Processes
Presenter: S. Dasari, University of Illinois at Chicago
Authors: S. Dasari, University of Illinois at Chicago
M. Hashemian, University of Illinois at Chicago
E. Karpov, University of Illinois at Chicago
Correspondent: Click to Email
Studies of chemically induced hot electron flow over Schottky barriers in planar metal-semiconductor nanostructures provides interesting possibilities for electrolyte-free conversion of chemical energy into electricity in solid-state devices and ultra-fast sensor applications. A method is described here to separate the hot electron current contribution to the total generated current based on in-situ resistive heating of cathode nanolayer of the Schottky structure. The total current is comprised of the hot electron and thermal components. The method preserves usability under application-relevant conditions requiring lower sample temperatures and higher pressures of a reactive gas mixture. Analysis of the current induced during oxidation to water of molecular hydrogen in 60-150 Torr mixtures on Pt/n-GaP nanostructure surface at 341-433 K is performed. Hot electron contribution to the total current has a nonmonotonic dependence on temperature, and its fraction reaches 25% at 341 K and 32% at 433 K. We also found that adsorption of molecular hydrogen and nitrogen gases on Pt/SiC planar nanostructure at normal atmospheric conditions leads to generation of a detectable chemicurrent only in the case of hydrogen. Nitrogen admission conditions were tuned to imitative an equal or greater thermal effect of adsorption as observed during admission of hydrogen gas; therefore the recorded chemicurrent cannot be thermally driven. Adsorptive chemicurrents can occur from admission of hydrogen to samples not only at pre-vacuum conditions, as in earlier studies, but also in reactive and inert gas mixtures at normal atmospheric pressure.