Electrochemical nanocell

Due to ambient humidity, one or very few layers of absorbed water formed due to condensation results in the formation of water meniscus between the conductive tip and the substrate. Thus highly resistive electrolyte is formed by a thin water film in wet gas atmosphere which facilitates formation of nanostructures by oxidation of the metal substrate. The introduction of reference electrode in the electrochemical nanocell is not at all possible due to space constraint. A large potential drop in the electrolyte and at the counter electrode, i.e., AFM tip is encountered due to the absence of reference electrode. Several attempts have been made for nanostructure formation on metal substrates such as Si,... 

Ti, and Nb by AFM tip induced nano oxidation with the help of forming electrochemical nanocell. A typical nanocell utilizing AFM tip for formation of Si02 nanostmcture is shown in Fig. 13.3 [10]. Figure 13.3 schematically represents different phases of electrochemical nanocell where AFM tip acts as a cathode and Si substrate acts as an anode. 

H. BloeB, G. Staikov, J.W. Schultze, AFM induced formation of Si02 structures in the electrochemical nanocell, Electrochim. Acta 47 (2001) 335-344. 

Nanocell is the smallest electrochemical cell developed by Sugimura and Nakagiri [11] and further developed and utilized for ENT by BloeB et al. [10]. The nanocell consists of two electrodes distance between electrodes is generally maintained in the order of less than 1 nm. In between two electrodes, absorbed water film acts as an electrolyte whose volume is maintained by vapor pressure and ranges from 10 to 10 cm. Double layer capacitance is not formed across the solid liquid interface in the nanocell due to the much smaller inter-electrode gap and hence, generated hydrogen ion and hydroxyl ion recombine immediately. Nanotip of microtool such as tip of scanning probe microscope (SPM) or AFM tip is most suitable for the formation of electrochemical nanoceU. 

---