Electrodeposition of nanoscale

D. Hoffmann, W. Schindler, J. Kirschner. Electrodeposition of nanoscale magnetic structures. Appl. Phys. Lett. 73, 3279-3281, 1998. 

Abedin SZE, Borissenko N, Endres F (2004) Electrodeposition of nanoscale silicon in a room temperature ionic liquid. Electrochem Commun 6 510-518... 

Rhodes, C.P., J.W. Long, and D.R. Rohson, Direct electrodeposition of nanoscale solidpoly-mer electrolytes via electropolymerization of sulfonated phenols. Electrochemical and Solid State Letters, 2005. 8(11) pp. A579-A584... 

Nanoscale electrodeposition of Ge on Au(lll) from an ionic liquid has been studied ]494] utilizing in situ STM. At underpotentials, a thin rough layer is formed. 

The electrodeposition of silver from chloroaluminate ionic liquids has been studied by several authors [45-47], Katayama et al. [48] reported that the room-temperature ionic liquid l-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4) is applicable as an alternative electroplating bath for silver. The ionic liquid [EMIM]BF4 is superior to the chloroaluminate systems since the electrodeposition of silver can be performed without contamination of aluminum. Electrodeposition of silver in the ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) and l-butyl-3-methylimidazoliumhexafluorophosphate was also reported [49], Recently we showed that isolated silver nanoparticles can be deposited on the surface of the ionic liquid Tbutyl-3-methylimidazolium trifluoromethylsulfonate ([BMIMJTfO) by electrochemical reduction with free electrons from low-temperature plasma [50] (see Chapter 10). This unusual reaction represents a novel electrochemical process, leading to the reproducible growth of nanoscale materials. In our experience silver is quite easy to deposit in many air- and water-stable ionic liquids. 

In this chapter we present a few selected results on the nanoscale electrodeposition of some important metals and semiconductors, namely, Al, Ta and Si, in air- and water-stable ionic liquids. Here we focus on the investigation of the electrode/electrolyte interface during electrodeposition with the in situ scanning tunneling microscope and we would like to draw attention to the fascinating... 

Comparing this approach with previous work - except the studies on solid electrolytes - ionic liquids have two distinct advantages over aqueous or organic solvents (i) Due to their extremely low vapor pressure ionic liquids can be used without any problem in standard plasma vacuum chambers, and the pressure and composition in the gas phase can be adjusted by mass flow controllers and vacuum pumps. As the typical DC or RF plasma requires gas pressures of the order of 1 to 100 Pa, this cannot be achieved with most of the conventional liquid solvents. If the solvent has a higher vapor pressure, the plasma will be a localised corona discharge rather than the desired extended plasma cloud, (ii) The wide electrochemical windows of ionic liquids allow, in principle, the electrodeposition of elements that cannot be obtained in aqueous solutions, such as Ge, Si, Se, A1 and many others. Often this electrodeposition leads to nanoscale products, as shown e.g. by Endres and coworkers [60]. 

Refs. [i] Wolf S (2002) Silicon processing for the VLSI era, deep-submicron process technology, vol 4. Lattice Press, Sunset Beach [ii] An-dricacos PC (1999) Interface 8 32 [iii] Stickney JL (2002) Electrochemical atomic layer epitaxy (EC-ALE) Nanoscale control in the electrodeposition of compound semiconductors. In Alkire RC, Kolb DM (eds) Advances in electrochemical science and engineering vol 7 Wiley-VCH, Weinheim, pp 1-106... 

The coarse-grained approach utilizes a simplified system representation with fewer degrees of freedom, resulting in faster simulations but with reduced spatial and/or temporal resolution [97-99]. Different coarse-graining (CG) schemes have been devised to preserve the most relevant properties of the molecular system. Such methods can be applied to describe time scales that are far beyond the scope of allatom M D or KMC simulations, and thus extend the scope of molecular simulation to the nanoscale. Some examples of successful application of CG methods are the simulation of the different phases of the lipid-water system, interactions of peptides and proteins with biological membranes, and the electrodeposition of copper to form nanowires, nanofilms and nanoclusters in kinetic-limited regimes [182]. 

Stickney, J.L. (2002) Electrochemical Atomic Layer Epitaxy. Nanoscale Control in the Electrodeposition of Compound Semiconductors. Advances in Electrochemisty Science and Engineering (eds R.C. Alkire and D.M. Kolb), Wiley-VCH, Weinheim, vol. 7, pp. 1-106. 

The electrode surface roughness at low level of coarseness can be increased in some different ways other than dendrites (spongy-like deposit,33 honeycomb-like structure,76,77 pyramid-like deposit,83 etc.) on the microscale. The properties of electrodeposits on nanoscale should be also taken into consideration.84,85 Further investigation will show which one of them is the best for this purpose. This chapter is written in order to initiate it. 

Endres F, Abedin SZE (2002) Nanoscale electrodeposition of germanium on Au(l 11) from an ionic liquid an in situ STM study of phase formation, part I Ge from GeBr. Phys Chem Chem Phys 4 1640-1648... 

Freyland W, Zell CA, Abedin SZE et al (2003) Nanoscale electrodeposition of metals and semiconductors from ionic liquids. Electrochim Acta 48 3053-3058... 

Brankovic SR et al (2006) Pulse Electrodeposition of 2.4 T Co Fe alloys at nanoscale for magnetic recording application. IEEE Trans Magn 42 132-139... 

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