Synthesis of nanoobjects
Abstract
Top-down and bottom-up approaches have been developed for the synthesis ofnanoobjects [1]. Top-down ones include, for example, milling and attrition forparticles in the range from 10 nm to several hundred nanometers in diameter.However, these techniques exhibit large size and shape distributions, and significantamounts of impurities from the treatment medium or defects from the process itself.Bottom-up approaches are much more preferred through many different processes asthey generally show more convincing results in terms of uniformity in size, shape andchemical composition distributions. Generally, nanoparticles are synthesized byhomogenous nucleation in the liquid phase or in the gas phase, and nanowires ornanotubes are synthesized by heterogeneous nucleation on a substrate. Fundamentalaspects of nucleation and growth are presented prior to a presentation of differentsynthesis processes.