Developing an AFM-Based SECM system; Instrumental setup, SECM simulation, characterization, and calibration
2008 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 155, no 8, C474-C485 p.Article in journal (Refereed) Published
An integrated atomic force microscopy/scanning electrochemical microscopy (AFM/SECM) system was developed as an in situ local electrochemical probing technique. It consists of a dual-mode probe acting as an AFM cantilever and SECM microelectrode to simultaneously obtain the topography and electrochemical current map of the same area. Two types of probes with different geometries were used. The scan velocity and concentration profile of the redox mediator during the scan were simulated, using the equations of convection-diffusion mass transport coupled with continuity and momentum in three dimensions under steady-state and transient conditions. The temporal and spatial resolutions of the probes were investigated. It was found that, during a normal scan rate (around 1 Hz), the effect of convective transport is negligible and the SECM lateral resolution depends on the geometrical parameters. With favorable geometry, a probe with a Pt microelectrode of 1 mu m diameter can distinguish two active sites with a distance of at least 3-4 mu m. The paper also reports experiments for characterization and calibration of the AFM/SECM system. Concurrent AFM and SECM images obtained on a gold band calibration sample verify the high-resolution capability of the SECM of one or a few micrometers with optimized conditions.
Place, publisher, year, edition, pages
2008. Vol. 155, no 8, C474-C485 p.
Atomic force microscopy, Calibration, Equations of state, Geometry, Gold, Microelectrodes, Mobile telecommunication systems, Platinum, Surface defects, Thickness measurement
IdentifiersURN: urn:nbn:se:kth:diva-24432DOI: 10.1149/1.2943324ISI: 000257421600030ScopusID: 2-s2.0-46649095279OAI: oai:DiVA.org:kth-24432DiVA: diva2:349732
QC 201009082010-09-082010-09-082012-03-20Bibliographically approved