Scanning electrochemical microscope induced

The SECM can be used in the feedback mode to probe lateral mass-charge transfer [79-83]. The theory of SECM feedback surveyed in Section IV.A.2 assumes that the substrate surface is uniformly reactive. When lateral mass and/ or charge transfer occurs on the substrate surface, or within a thin film, the surface reactivity of the substrate becomes non-uniform and the SECM feedback theory must be modified. Unwin and Bard [79] developed the theory for adsorption-desorption of a redox species at the substrate that allowed for surface diffusion of the adsorbate. They introduced a new approach, the scanning electrochemical microscope induced desorption (SECMID), as a way to probe surface diffusion. The set of differential equations for the diffusion problem comprise Eqs. (8a,b), and Eq. (26), which relates the redox concentration at the substrate surface and the surface coverage by adsorbed species... 

Macpherson JV, Unwin PR (1996) Scanning electrochemical microscope-induced dissolution theory and experiment for silver chloride dissolution kinetics in aqueous solution without supporting electrolyte. J Phys Chem 100(50) 19475-19483. doi 10.1021/jp9614862... 

Unwin PR, Bard AJ (1992) Scanning electrochemical microscopy. 14. Scanning electrochemical microscope induced desorption - a new technique for the measurement of adsorption desorption-kinetics and surface-diffusion rates at the solid liquid interface. J Phys Chem 96(12) 5035-5045... 

Macpherson, J. V., Unwin, P. R. Scanning electrochemical microscope induced dissolution Rate law and reaction rate imaging for the dissolution of the (010) face of potassium ferrocyanide trihydrate in non-stoichiometric aqueous solutions of the lattice ions. J. Phys. Chem. 1995, 99, 3338. 

The kinetics of AgGl dissolution in aqueous solutions without supporting electrolyte have been studied utilizing well-defined and high mass transport properties of the scanning electrochemical microscope [376]. An ultramicroelectrode probe positioned close to the AgGl surface was used to induce and monitor dissolution of the salt via reduction of Ag+ from the initially saturated solution. 

Treutler, T.H., and G. Wittstock. 2003. Combination of an electrochemical tunneling microscope (ECSTM) and a scanning electrochemical microscope (SECM) Application for tip-induced modification of self-assembled monolayers. Electrochim. Acta 48 2923-2932. 

SECM (Scanning electrochemical microscopy) is a technique to characterize the local electrochemical nature of various materials by scanning a probe microelectrode [1,2]. The spatial resolution of SECM is inferior to the conventional scanning probe microscopes such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM) as the fabrication of the probe, microelectrode, with nanometer sizes is quite difficult and the faradaic current of the microprobe is very small (often picoamps or less). However, SECM has unique characteristics that cannot be expected for STM and AFM SECM can image localized chemical reactions and it also can induce localized chemical reactions in a controlled manner. 

The scanning probe microscope can be used to write nanostructures onto surfaces. Penner has used the scanning tunneling microscope (STM) to modify a surface with nanometer-scale defects, so as to induce nucleation of the deposited material at these defect sites In another method, pioneered by Dieter Kolb, metal nanostructures are produced by electrochemically depositing the metal onto the STM tip and then transferring the material to the surface during the tip approach. - An example of a corral of Fe nanoclusters on Au(lll) produced by this method is shown in Figure 17.13. ... 

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