Nanotechnology deals with the study, development and practical application of structures and devices at molecular scale (between 1 and 100 nanometers, one nanometer is
equivalent to 1 in 10-9 meters). "Nano" is a Greek prefix, which signifies a "billionth" (one billionth of a meter is
the unit of measure in the field of nanotechnology). An atom is smaller than a nanometer, but a molecule can be larger.
2. Types of Nanotechnologies
A) Top-Down (larger to smaller size):Here, the mechanisms and structures are miniaturized to a nanometric scale. This approach is widely following in the miniaturization of electronic
products, and electronic components manufacturing processes.
B) Bottom-Up (Smaller to larger size): Here, we begin with a nanometric structure such as a molecule, and through a process of molecular level
assembly, a bigger product is generated. The ultimate step for Bottom-Up Nanotechnology is called "molecular nanotechnology", or
"molecular manufacturing". Since the product is made by placing each molecule meticulously in a given position, many believe that the bottom-up approach is the true nano
technology, where further miniaturization is not possible.