ZnO NANOSTRUCTURES AND ITS LUMINESCENT PROPERTIES
Nanotechnology deals with materials or structures in nanometer scales (10−9 m), typically ranging from sub nanometers to several hundreds of nanometers. Earlier common notion was that material properties can be changed only by varying the chemical composition. But later it has been found that the material properties can be tuned by varying the size of the material without changing the chemical composition. The transition from micron sized particles to nanoparticles leads to a number of changes in their physical properties. The major change is the increase in the surface area to volume ratio, as the size of the particle reduces. These new properties or phenomena will not only satisfy everlasting human curiosity, but also promise a new advancement in technology. Another very important aspect of nanotechnology is the miniaturization of current and new instruments, sensors, and machines that will have great impact on the world we live in. Nanotechnology has an extremely broad range of potential applications from nanoscale electronics and optics to nanobiological systems.