First of all we must know what nano technologyis. It is the technology which makes materials very much smaller than they are at present. It is the technology that gives result to the high performance electronic devices which are much smaller in size than the usual ones.The term ‘nano’ came into frequent use in early 1990’s in scientific and industrial research, until then the more general term ‘submicron’& ‘ulmatine’ were used to define the smaller particles. One nanometer is one billionth of a meter, i.e. 10-9 m.

Nano particles are materials possessing micro structural dimensions less than 100nm. The small size of nano particles which is responsible for different properties (optical, magnetic, structural, electrical and electronic) with respect to the bulk materials makes them suitable for new application. These material manifest fascination and useful properties which can be exploited for a variety of application in electronic device fabrication (sensors,

LED, compact discs) and next generation computer chips.

Controlling a material’s properties at the molecular level is one of the challenges of advanced materials science. Synthesis of materials is the most vital part in obtaining desired properties.

Nanoparticles are prepared either by a ‘bottom up’ or a ‘top down’ process. “Bottom up” process involves process such as chemical reaction, tem plated synthesis or self assembly. In the “Top down” process nano particles are formed in a mill in which energy is imparted to a large grain material to reduce the particle size. Agglomeration of primary particles, high cost of production and a wide range of particle size distribution are the main disadvantage of the milling process. Chemical processing is a convenient way of producing nano materials in a predefined size and morphology. There are several known chemical methods to prepare nano materials including hydrothermal synthesis, emulsion synthesis, co-precipitation tem plated synthesis and sol-gel synthesis. Sol-gel processing is the most popular way of producing nanoparticles, which has advantage of higher purity, homogeneity and lower processing temperature.

In the area of magnetic storage media, future progress will relay on the ability to control the microstructure at smaller size scales so as to improve storage densities. The approach that will use magnetic nanoparticles of the size of a single magnetic domain is very important for development of high density magnetic recording material IBM re searchers in New York and California have recently made a new class of magnetic particles of iron and platinum each uniformly containing only a few hundreds of atom self-assembled in to ordered arrays using simple chemical reactions. This scientific discovery could lead to new solutions for storing a huge volume of data in much smaller CDs.

Researchers have created the 1^st functional logic circuit within a single molecule, an achievement that could one day help to replace silicon in micro chips. This is a significant step towards smaller, faster and less power consuming computers.

Carbon nanotubes are believed to be the top candidate to replace silicon when current chip features just can’t be made any smaller a physical barrier expected to occur in about 10-15 years. The new circuit works on a miniature scale, using a hollow carbon-tube approximately 1.4nm (nanometer) in diameter or approximate 100,000 times thinner than a human hair.

The researchers changed the nanotube’s electrical characteristics so that some section would allow the flow of electrons, while other sections would allow the flow of electric current using positive entities on the nanotube called positive holes.

Computers will eventually reach a maximum capacity with silicon that cannot be overcome, forcing the need for new materials capable of adding small computer circuits to maintain the advancements in future. The world’s smallest guitar carved out of crystalline silicon has been fabricated at cornell university. This guitar has 6 strings, each string about 50nm wide and the entire structure is about 10 micrometer (10-s m).this ‘nanoguitar’ was made for fun to illustrate the building up of smaller mechanical devices.

The physical and chemical properties of nanomaterials are different from bulk materials of same molecular structure. One of the basic concepts of the science of solids depends on the microstructure, ie chemical composition, the arrangement of atoms and the size of solid. If there is change in one or any of these parameters, the properties of solid vary. Nanoparticles can be considered as a state of matter in the transition region between bulk solids and molecular structure. The physical and chemical properties gradually change from molecular to bulk with particle size.

Limitations of this new technology

There are a few limitations associated with their new technology. Most of the materials produced by nanotech are in the small scale labs environment. One of the main challengers is the bulk production of these materials. Special measurement techniques and high resolution instruments are required to characterize those in many countries, the benefits of this technology would have to out weight the expenses in making changes in the current manufacturing process.

Nanotechnology thus holds tremendous potential to improve our quality of life in the near future by offering high performance devices in smaller dimensions.