Top-down and bottom-up approaches

There are two types of approaches for the synthesis of nanomaterial and fabrication of nanostructure.

top-Down approaches refers to slicing or successive cutting of bulk material to get nano-sized particles.there are two types *attrition ,* milling

Bottom-up refers to method where devices 'create themselves' by self-assembly. Chemical synthesis is a good example. Bottom-up should, broadly speaking, be able to produce devices in parallel and much cheaper than top-down methods, but getting control over the methods is difficult when things become larger and bulkier than what is normally made by chemical synthesis. Of course, nature has had time to evolve and optimize self-assembly processes that can do wonders.

Microfabrication made smaller

Not much of nanotechnology is based on methods from Microfabrication.

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