Nanotechnology

• Understanding and control of matter at dimensions of 1 to 100 nanometers

• Ultimate aim: design and assemble any structure atom by atom - molecular manufacturing

Courtesy Office of Basic Energy Sciences,Office of Science, U.S. Department of Energy

Natural NanomachinesATP synthesis protein(courtesy Dr Christoph von Ballmoos)

DNA polymerase(biology-online.org)

HIV virus inside a cell(University of Buffalo, SUNY)

Agriculture – our first use of nature’s nanomachines

Chloroplasts in the green parts of theplant convert carbon dioxide in air into complex carbohydrate molecules rich in chemical energy. Chlorophyll moleculethat gives leaves and grasses their green color acts as an efficient catalyst activatedby sunlight

(Florida State University)

By throwing seeds in the ground, our ancestors invested wealth of energy of the seed for more wealth at harvest. Investment – a way to grow rich

How much are we investing in Nanotechnology today?

What we have

Scanning Tunneling Microscope (STM)1981 Binnig and Rohrer

The STM can obtain images of conductive surfaces at an atomicscale of 0.2 nm, and also can be used to manipulate individual atoms,trigger chemical reactions, or reversibly produce ions by removing or adding individual electrons from atoms or molecules.

STM allows manipulation of individual atoms (1989)

Xenon atoms spell IBM on a nickel plate(IBM)

Iron atoms spell “Atom” on copper in Kanji characters.(IBM)

What we have

Atomic Force Microscope (AFM)1986, Binnig, Quate and Gerber

The AFM provides a three-dimensionalsurface profile with vertical resolution of 0.1 nmand allows to manipulate and study individual molecules including biological macromolecules

AFM Manipulation of Single Walled Nanotube, 1999

Scaling down the microprocessor, the molecular logic gate.

This molecular gate performs addition

(Courtesy Professor A Prasanna de Silva)

Top Down Approach - NanomachiningNanolithographyTechniques

• Optical Lithography (Shortest wavelenght - 193nm)• Electron Beam Lithography• Extreme Ultra-Violet Lithography (Shortest wavelength –

13.5nm)• Ion projection Lithography• Nano-imprint Lithography• X-ray Lithography• Dip-Pen Lithography

Top Down Approach - NanomachiningNano-Imprint Lithography - NIL

Pattern is imprinted into a mold made of photo-resistant polymer

Mold is then used for thousandsof wafers to transfer the pattern

Layer of assembled nanostructurestransferred to a wafer

(NSF Center for High-Rate Nanomanufacturing)

Bottom Up Approach – Self-assembly

Creating novel molecules capable of assembling themselves into given superstructures is an important nanomanufacturing technique.

Fullerenes with functional groups attached to them self-assemble into a 3D structure.