APPLICATIONS OF SCANNING ULTRA MICRO ELECTRODES FOR STUDIES ON SURFACE CONDUCTIVITY

Applications of the constant distance mode recently discovered for Sca nning Electrochemical Microscopy (SECM) are presented. The new mode en ables the separate acquisition of a sample's electrochemical and morph ological information by detecting the faradaic current of the scanning probe. The morphology can be determined within fractions of a micron by bringing the tip close to the sample at high speed at varying later al positions. Convective effects increase the current in the sample's vicinity. To study the electrochemical properties laterally resolved, one compensates the morphological influence by moving the tip at a con stant distance from the surface's structure. The advantageous use of t he new mode is proven by scans of a homogeneous platinum sheet and a g lass substrate covered by a derivative of poly-terthiophene spots. The comparison with the experimental results obtained by the conventional constant height mode explains the progress of the new constant distan ce mode.