SCANNING ELECTROCHEMICAL MICROSCOPY - 36 - A COMBINED SCANNING ELECTROCHEMICAL MICROSCOPE QUARTZ CRYSTAL MICROBALANCE INSTRUMENT FOR STUDYING THIN-FILMS

The design of a combined scanning electrochemical microscope-quartz cr ystal microbalance (SECM-QCM) with separate potential control of the t ip and substrate is described. Both lateral and vertical tip movements near the substrate affect the QCM resonant frequency because of pertu rbations of the longitudinal and shear waves of the quartz crystal (QC ) acoustic wave sensor. The SECM-QCM was used to study etching of a th in Ag layer deposited on the QC contact by generating an etchant, iron (III) tris(bipyridine), at the tip near the surface. The SECM-QCM was also used to monitor film mass and surrounding electrolyte composition during potential cycling of a film of C-60 on an electrode.