Regensburg 2000 – scientific programme
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O: Oberflächenphysik
O 14: Adsorption an Oberflächen (III)
O 14.1: Talk
Tuesday, March 28, 2000, 11:15–11:30, H36
STM measurements of current/potential curves at a semiconductor surface — •Renate Hiesgen1 and Dieter Meissner2 — 1Technische Universitaet Muenchen, Physikdepartment E19, James-Franck-Str. 1, D-85748 Garching, Germany — 2Technische Universitaet Linz, Physikalische Chemie, Altenberger Str. 69, A-4040 Linz, Austria
A new experimental method for the analysis of current-potential curves determined with a scanning tunneling microscope in an electrochemical cell is described. Spectroscopic mesurements have been performed in sulphuric acid at a tungsten diselenide semiconductor sample. Measurements of current/voltage curves obtained with the STM for different tunneling gaps and for different potentials of the tip and the semiconductor are recorded and results are shown. Current/distance curves obtained from these measurements allow to separate the influence of the tunneling barrier from that of the Schottky barrier at the semiconductor/electrolyte interface. Changes in the barrier heights are due to an electronic influence from the tip potential on the semiconductor surface potential when the tip enters the electrochemical double layer.