NANOTECHNOLOGY The shotgun marriage of chemistry and engineering called " Nanotechnology" is ushering in the era of self - replicating machinery and self assembling consumer goods made from raw atoms. Utilizing the well understood chemical properties of atoms and molecules , nanotechnology proposes the construction of novel molecular
devices possessing extraordinary properties. The single electron transistor or SET is new type of switching devices that uses controlled electron
tunneling to amplify current. By using the "Electron beam lithography" and " Electromigration ", the research leads to the designing of a single atom transistor with the help of meticulously synthesized semiconductor crystals called "quantum dots", which embodies the
electrons confined in a channel and resembles same in its properties as an real atom. This paper presents a scenario on existing and ongoing studies on NANO ELECTRONICS with the theoretical methods relevant to their understanding. Most of the preceding discussion is premised upon the implicit assumption. That future quantum effect Nano Electronic Devices will be fabricated in Nano Meter scale using molecules. Conductance quantization in ballistic regime has been described under various conditions. The behaviour of " Coulomb Island" through which the electrons can only enter by tunneling through one of the insulators is presented. At last, the SET presents that it is the different construction is which is based on helical logic, atomic scale motion of electrons in an applied rotating electric field.