Nano-Sized Structures on Atomically-Flat Semiconductor and Metal Surfaces, Formed by Chemical and Electrochemical Methods

The self-organizing abilities of molecular and nano-sized systems have been explored to form ordered nano-sized structures. Some germinant unique examples of such nano-structures, produced by chemical and electrochemical methods, are reviewed. The first example is formation of nano-holes at atomically flat, H-terminated n-Si (111) surfaces, which occurs during electrochemical deposition of Pt. Reductive dissolution of the Si surface, catalyzed by Pt in a mono-atomic state as a reaction intermediate of the Pt deposition, is proposed as a plausible mechanism. The second example is formation of ordered iodine nano-rods on atomically flat, H-terminated n-Si (111) surfaces, which occurs upon their immersion in 7.1 M HI. The formation of iodine nano-rods was closely related with that of Si-iodine termination bonds. The third example is formation of ordered arrays of gold nano-particles in aqueous solutions and on gold (111) surfaces, which occurs by addition of organic thiols to particle solutions. The aspect ratio of the ordered arrays depended on the kind of thiols added. These examples strongly suggest that the chemical and electrochemical methods are a promising approach to production of ordered nano-structures on solid surfaces.