ABSTRACT
Microelectronics and nanoelectronics are made by top-down approaches. Another way to manufacture nanoscale devices is to use atoms, single or group of molecules, carbon nanotubes, metallic or semiconductor nanowires as the elementary components and find methods to assemble them in the right way to perform electronic functions. This is the essence of molecular electronics called also moletronics. Sometimes, the term molecular electronics is restricted to the use of single molecules only but, for applications, it is better to use an extended definition involving nanoscale components. It is not an easy task to develop bottom-up approaches because nanoscale objects already contain a large number of molecules and atoms and the main issue is to assemble them correctly and quickly in the right way.
