Fabrication of a ring nanoelectrode in an AFM tip: novel approach towards simultaneous electrochemical and topographical imaging

Abstract

We present a novel approach for the fabrication of a ring nanoelectrode integrated in a standard atomic force microscopy (AFM) tip. The discussed procedure enables the integration of an electroactive area in an exactly defined distance above the apex of a scanning probe tip and the subsequent remodelling and sharpening of the original AFM tip using a focused ion beam technique. This approach is a novel concept towards enhancing the functionality of AFM in order to obtain laterally resolved electrochemical information. Hence, entirely separated topographical and electrochemical information can be obtained simultaneously. The presented technique also demonstrates an alternative approach towards electrochemical imaging using nanometer electrodes with a well-defined geometry, as shown with the development of the first integrated ring nanoelectrode in an AFM cantilever.

Developing an AFM-Based SECM System; Instrumental Setup, SECM Simulation, Characterization, and Calibration

“…[13][14][15][16][17][18][19][20][21][22][23][24] In the present study, a microchip gold band was used for calibration of the AFM/SECM probes. The microchip gold bands were inserted in an insulating substrate.…”

Advective and transient effects in combined AFM/SECM operation

“…(15), with the boundary conditions in Eq. (24), and the location of the boundary between oX insulator and oX conductor moves with the velocity of the substrate.…”

“…In the case of a disk electrode located adjacent to the AFM tip, the tip could hinder diffusion from one direction, complicating data interpretation. To avoid this problem, a frame [11] or ring [15] electrode can be used with the tip located centrally. Alternatively, the AFM tip itself may be coated with a conducting material to serve as the electrode [16,17]; however, the resultant contact between the electrode and substrate can limit the utility of this method [18].…”

Electrochemical current-sensing atomic force microscopy in conductive solutions

“…Kranz et al pioneered the development of AFM probes with an integrated recessed frame [18][19][20][21] or ring [22,23] platinum nanoelectrodes of controlled dimensions around a non-conductive tip for application in combined AFM-scanning electrochemical microscopy (SECM) experiments. These probes were insulated with various coatings, such as Si 3 N 4 [18,22], SiO 2 [23], Si 3 N 4 /SiO 2 sandwich layers [19], poly(p-xylylene) (parylene) [20] or plasma-deposited fluorocarbon films [21]. Recently, the group of Kranz reported on diamond-coated tips with integrated boron-doped diamond (BDD) nanoelectrodes [24].…”