David O. Wipf: https://orcid.org/0000-0003-2365-1175
Mario A. Alpuche-Aviles: https://orcid.org/0000-0003-2615-4115
A new constant-distance imaging method based on the relationship between tip impedance and tip-substrate separation has been developed for the scanning electrochemical microscope (SECM). The tip impedance is monitored by application of a high frequency ac voltage bias between the tip and auxiliary electrode. The high frequency ac current is easily separated from the dc level faradaic electrochemistry with a simple RC filter, which allows impedance measurements during feedback or generation/collection experiments. By employing a piezo-based feedback controller we are able to maintain the impedance at a constant value and, thus, maintain a constant tip-substrate separation. Application of the method to feedback and generation/collection experiments with tip electrodes as small as 2 mm is presented.
College of Arts and Sciences
Department of Chemistry
Scanning probe microscopy, SECM, impedance, position control, electrochemistry, ultramicroelectrode
Wipf, David O. and Apuche-Avlles, Mario A., "Impedance Feedback Control for Scanning Electrochemical Microscopy" (2001). College of Arts and Sciences Publications and Scholarship. 29.