| AVS 59th Annual International Symposium and Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS+EN+OX-ThM |
| Session: | Catalysis and Photocatalysis on Oxides |
| Presenter: | S.V. Simchenko, Azov State Technical University, Ukraine |
| Authors: | S.V. Simchenko, Azov State Technical University, Ukraine V. Styrov, Azov State Technical University, Ukraine |
| Correspondent: | Click to Email |
Since the recent discovery of production of electronic flows in Schottky diodes with nanosized “top” metal layer due to ballystic metal-to-semiconductor transport of hot electrons formed by the surface exoergic chemical reaction, e.g. [1], this effect attracts attention of scientists owing to its fundamental and practical potential. Here we invastigate a new system of that kind, namely Pd-(n)GaP planar Schottky diod (15 nm Pd-layer) placed in the atmosphere of atomic hydrogen. We found the steady-state current flow through the system under consideration in perpendicular direction to the metal surface on which the hydrogen atoms stationary recombine into molecules.
We elaborated a new approach to detect production of the inequilibrium charge carriers via nonadiabatic channel by observing the current-voltage characteristic of the Schottky diode in the presence and absence of the atomic flux incident on the structure. The nonequilibrium nature of the additional carriers is confirmed by kinetics measurements: the current drops to its initial value in the absense of atoms practically momentarily once the atoms are “switched off” and jumps immediately to its excited value when atoms are “switched on” (at the given temperature of the structure and the fixed forward voltage bias on the structures). We were able to draw some quantitative information about the processes of generation of nonequilibrium electron-hole pairs in the reaction of recombination of hydrogen atoms on Pd-surface and their transport in the metal film. The short circuit current is expressed in terms of yield of the chemoexcited carriers and probability of their survival while traveling through the Pd-film.
For a 1V forward bias the current drastically grows from 3 nA to 950 uA; thus the bias allows gaining chemicurrent value as large as five orders of magnitude. This result can be of significant importance for the practical applications of the nonequilibrium chemiconductance and chemicurrents in Schottky nanostructures including sensing and chemical-to-electricity energy conversion.
[1] B. Georgen, H.Nienhaus, W.H. Weinberg, E. McFarland. Science, 294, 2521 (2003)