Methods of preparation of nanomaterials

There exist many methods for the preparation of nanomaterials. These methods are broadly classified into two: top-down approach and bottom-up approach. Milling (mechanical grinding) and lithography are examples of top-down methods. . During milling, balls in the vial impart energy to powder material splitting them further to nanoscale. Lithography deals with the nanoelectromechanical systems which can be developed by using light, electron beam or ion beam. Wet chemical methods, plasma chemical methods, sol gel methods, physical vapour deposition, chemical vapour deposition, sputtering, Laser ablation, Molecular beam epitaxy, thermolysis, electrodeposition, Self assembly method etc are examples of bottom-up methods.