Nanotechnology Fabrication Methods

This Seminar Report is submitted in partial fullfillment for the award of the degree of MASTER OF TECHNOLOGY IN MACHINE DESIGN.

BY

P.KAMAL CHAITANYA 14331D1510MVGR COLLEGE OF ENGINEERING, VIZIANAGARAM

OverviewIntroductionNanomaterialsHistoryExperimental AdvancesFabrication MethodsConclusionReferences

Nanotechnology It is defined as the manipulation of matter with at least one dimension sized from 1 to 100 nanometres, especially the manipulation of individual atoms and molecules.

Fig 1: Size of things in nanoscale

1 nm = 10^-9 m scale

Fig 2: Nanomaterials

History The American physicist Richard Feynman lectured, "There's Plenty of Room at the Bottom," at an American Physical Society meeting at Caltech on December 29, 1959.

The Japanese scientist called Norio Taniguchi of the Tokyo University of Science was the first to use the term “Nano-technology" in a 1974.

In the 1980s the idea of nanotechnology as a deterministic, rather than stochastic, handling of individual atoms and molecules was conceptually explored in depth by K. Eric Drexler.

Experimental Advances

The scanning tunneling microscope, an instrument for imaging surfaces at the atomic level, was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory

Fig 3: Scanning tunneling microscope and its schematic view

Scanning Tunneling Microscope

Fig 4: Image of surface reconstruction on a clean Gold (Au(100)) surface

Advances in interface and colloid science

The first observations and size measurements of nanoparticles had been done by Richard Adolf Zsigmondy, who made a detailed study of gold sols and other nanomaterials with sizes down to 10 nm using an ultramicroscope .

In the 1920s, Irving Langmuir, winner of the 1932 Nobel Prize in Chemistry, and Katharine B. Blodgett introduced the concept of a monolayer, a layer of material one molecule thick.

In 1974 the process of atomic layer deposition for depositing uniform thin films one atomic layer at a time was developed and patented by Tuomo Suntola and co-workers in Finland

Discovery of Fullerence

Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley, and Robert Curl.

A fullerene is a molecule of carbon in the form of a hollow sphere, ellipsoid, tube, and many other shapes.

Spherical fullerenes are also called Buckminsterfullerene (buckyballs).

Cylindrical ones are called carbon nanotubes or buckytubes. Fig 5: Buckminsterfullerene C60

(left) and carbon nanotubes (right) are two examples of structures in the fullerene family.

Fabrication MethodsFabrication of nano materials includes nanostructured surfaces, nanoparticles, nanoporous materials.

Fabricating nanomaterials can be classified in to two groups:1. Top-Down Method and2. Bottoms–Up Method

Top-Down Method: In this method nanomaterials are derived from a bulk substrate and obtained by progressive removal of material, untill desired nanomaterial is obtained.

Fig 6: Carving a Statue from Marble

Bottom-Up Method: In this method nanomaterials are obtained starting from the atomic or molecular precursors and gradually assembling it untill the desired structure is formed.

In both the metods there are two requisites:1. Control of fabrication condition (eg: Energy of the electron

beam)2. Control of environment conditions (eg: Dust and Conditions)

Fig 7: Lego-Bricks.

Lithiography: It follows the principal of transferring an image from the task to a receiving substrate.

1. Coating a substrate (si wafer)with a sensitive polymer layer(resist).

2. Exposing the resist with light, electrons or ion beams.3. Developing the resist image with a suitable

chemical(developer).

Fig 8: Photo Lithiography ProcessThe next process after lithiography is pattern transfer from resist to substrate and it is done by using chemical and dry plasma etching.

Lithiography techniques can be broadly classified in to two groups:1. Photo Lithiography2. Scanning Lithiography

Fig 9: Scanning Lithiography

The other known lithiography methods are:

• E-beam Lithiography• Soft- Lithiography• Nano-Imprint Lithiography• Nanosphere Lithiography• Colloidal Lithiography

Fig 10: Nano-Imprint Lithiography

Nanosphere Lithiography

Fig 11: Nanosphere Lithiography

Bottom-Up Methods

Bottom-Up Methods

Gas Phase Methods

Plasma arcing

Chemical Vapor

Deposition

Liquid Phase Methods

Sol-Gel Synthesis

Molecular Self

Assembly

Plasma arcing:

• Used for fabricating nanotubes.• Uses ionized gas (plasma).• Used to deposit nanolayers on surface from few atoms to 1nm thick

Fig 12: Plasma Arcing

Chemical Vapor Deposition:

• Used to make nanopowders of oxides or carbides.• Deposited Material is first heated to gas form.• Used to deposit material on flat surface.

Fig 13: Chemical Vapor Deposition

Sol-Gel Synthesis:

The sol‐gel process involves four steps:1. Hydrolysis, 2. Condensate3. Polymerization and 4. Agglomerate

Fig 14: Sol-Gel Synthesis

Molecular Self Assembly:

Self‐assembly is the “fabrication tool” of Nature: All natural materials, organic and inorganic, are produced through a self‐assembly route. In natural biological processes, molecules self‐assemble to create complex structures with nanoscale precision. Examples are the formation of the DNA duple helix or the formation of the membrane cell from phospholipids.  In self‐assembly, sub units spontaneously organize and aggregate into stable, well defined structures through non covalent interaction. This process is guided by information that is coded into the characteristics of the sub units and the final structure is reached by equilibrating to the form of the lowest free energy.

ConclusionThe Next Big Thing Is Really Small

Nanotechnology has a lot of scope in the present and near future as it can be applied to the various fields of science and as the nanomaterials enhances the properties of material along with exhibiting new properties.

References:http://wikipedia.com/http://nano.cancer.gov/learn/understanding/http://www.nano.gov/nanotech-101/what/nano-sizehttps://lorryseesthelight.wordpress.com/tag/social-media/http://www.nanoyou.eu/component/content/article/87-hands-on-activities/499-experiment-on-natural-nanomaterialsec3b.html?directory=94&Itemid=94http://hubpages.com/animals/Toucans-One-of-the-Most-Interesting-and-Amazing-Birdshttp://theinstitute.ieee.org/technology-focus/technology-topic/everyday-nanotechnologyhttps://www.buzzfeed.com/thewilsoncenter/29-everyday-products-you-didnt-know-contain-nanom-bh9khttp://nanolithography.spiedigitallibrary.org/article.aspx?articleid=2330541https://www.researchgate.net/figure/221907469_fig8_Fig-8-Chemical-nanoimprint-nanoelectrode-lithography-Yokoo-Namatsu-2009http://www.slideshare.net/NANOYOUproject/fabrication-methods-nanoscience-and-nanotechnologies