Introduction to Nanotechnology July 23, 2007 bnl manchester

Some things we will discuss: Introduction to Nanotechnology July 23, 2007 Some things we will discuss: How big are nanostructures Scaling down to the nanoscale How are nanostructures made? Fabrication, synthesis, manufacturing How do we see them? Imaging and property characterization (measurement) Why do we care? Applications to science, technology and society

Why do we want to make things at the nanoscale? To make better products: smaller, cheaper, faster and more effective. (Electronics, catalysts, water purification, solar cells, coatings, medical diagnostics & therapy, etc) To introduce completely new physical phenomena to science and technology. (Quantum behavior and other effects.)

Nanotechnology Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications. 1 nanometer = 1 x 10-9 m = 1 billionth of a meter nano.gov

How small are nanostructures? Single Hair Width = 0.1 mm = 100 micrometers = 100,000 nanometers ! 1 nanometer = one billionth (10-9) meter

Smaller still DNA 3 nanometers 6,000 nanometers Hair Red blood cell .

Down to the Nanoscale

From DOE

A Few Nanostructures Made at UMass 100 nm dots 70 nm nanowires 200 nm rings 150 nm holes 18 nm pores 12 nm pores 14 nm dots 13 nm rings 25 nm honeycomb 14 nm nanowires

"Nano" Nanoscale - at the 1-100 nm scale, roughly Nanostructure - an object that has nanoscale features Nanoscience - the behavior and properties of nanostructures Nanotechnology - the techniques for making and characterizing nanostructures and putting them to use Nanomanufacturing - methods for producing nanostructures in reliable and commercially viable ways

Nanotechnology R&D is interdisciplinary and impacts many industries Physics Chemistry Biology Materials Science Polymer Science Electrical Engineering Chemical Engineering Mechanical Engineering Medicine And others Electronics Materials Health/Biotech Chemical Environmental Energy Aerospace Automotive Security Forest products And others

An application example: Nanoelectronics

Making Small Smaller An Example: Electronics-Microprocessors microscale nanoscale macroscale ibm.com

Electronics Keep On Getting Better Moore's "Law": Number of Transistors per Microprocessor Chip intel.com

Since the 1980's electronics has been a leading commercial driver for nanotechnology R&D, but other areas (materials, biotech, energy, etc) are of significant and growing importance. Some have been around for a very long time: Stained glass windows (Venice, Italy) - gold nanoparticles Photographic film - silver nanoparticles Tires - carbon black nanoparticles Catalytic converters - nanoscale coatings of platinum and palladium

nano.gov "Biggest science initiative since the Apollo program"

National Nanotechnology Initiative Research Areas (2007 Federal Budget) Fundamental Nanoscale Phenomena and Processes Nanomaterials Nanoscale Devices and Systems Instrumentation Research, Metrology and Standards for Nanotechnology Nanomanufacturing Major Research Facilities and Instrumentation Acquisition Societal Dimensions

A National Science Foundation Nano Center nanomanufacturing.org A National Science Foundation Nano Center

Nanostructures

Nanostructures nanofilm, macroscale (3D) object or nanolayer (2D) height depth width nanoparticle, nanodot, quantum dot (0D) nanowire, nanorod, or nanocylinder (1D)

Making Nanostructures: Nanofabrication Top down versus bottom up methods Lithography Deposition Etching Machining Chemical Self-Assembly

Nanofilms (making an object thin)

An example of a FILM A monolayer NANOFILM (single layer of molecules) ~1 nm thick Langmuir film This is an example of SELF-ASSEMBLY

CHALLENGE: How thick was the film of oil? ... the Oil tho' not more than a Tea Spoonful ... ... perhaps half an Acre CHALLENGE: How thick was the film of oil? Volume = (Area)(Thickness) V = A t t = V/A = 2 cm3 20,000,000 cm2 V = 1 teaspoonful A = 0.5 acre ~ 2 cm3 ~ 2,000 m2 = 0.0000001 cm = 1 x 10-7 cm = 1 x 10-9 m = 1 nanometer (nm) 20,000,000 cm2

Langmuir Film of an amphiphilic molecule water hydrophobic end e.g., oleic acid pressure of an amphiphilic molecule monolayer film water hydrophilic end

Langmuir-Blodgett Film Must control movable barrier to keep constant pressure multiple dips - multiple layers

Another film method, Thermal Evaporation sample QCM Vaporization or sublimation of a heated material onto a substrate in a vacuum chamber film vapor Au, Cr, Al, Ag, Cu, SiO, others Pressure must be held low to prevent contamination! vacuum ~10-7 torr source There are many other thin film manufacturing techniques resistive, e-beam, rf or laser heat source vacuum pump

Lithography (controlling width and depth)

Mark Tuominen Mark Tuominen Lithography Mark Tuominen Mark Tuominen (Using a stencil or mask)

Making a nanoscopic mask Example: Electron-Beam Lithography Electron Beam Polymer film Silicon crystal Nanoscopic Mask !

Lithography Patterned Several IBM Times Copper Wiring On a Computer Chip

Self-Assembled Nanostructures

Self Assembly

Tobacco Mosaic Virus wisc.edu nih.gov

Gecko feet

Diatoms sinancanan.net priweb.org

Abalone

The Cell and Its Hierarchy ebi.ac.uk

Self assembly at all scales? Whitesides et al. Science 295, 2418 (2002);

NANOFABRICATION BY SELF ASSEMBLY One Example: Diblock Copolymers Block “B” Block “A” PS PMMA ~10 nm Scale set by molecular size Ordered Phases 10% A 30% A 50% A 70% A 90% A

Versatile, self-assembling, nanoscale lithographic system CORE CONCEPT FOR NANOFABRICATION Deposition Template Etching Mask Nanoporous Membrane (physical or electrochemical) Remove polymer block within cylinders (expose and develop) Versatile, self-assembling, nanoscale lithographic system

USING DIBLOCK COPOLYMER TEMPLATES NANOFABRICATION USING DIBLOCK COPOLYMER TEMPLATES template dots cylinders rings holes

Measuring Nanostructures

How do we see nanostructures? • A light microscope? Helpful, but cannot resolve below 1000 nm • An electron microscope? Has a long history of usefulness at the nanoscale • A scanning probe microscope? A newer tool that has advanced imaging

Television Set prelim. TV screen eye Light ! electron beam electron source

Scanning Electron Microscope Beam DETECTOR SAMPLE

(Atomic Force Microscope) "Optical Lever" laser pointer To determine amplification factor, use the concept of similar triangles

Scanning probe microscope Laser Beam Vibrating Cantilever PS/PEO AFM image µm (large ) Surface AFM, STM, MFM, others

Quicktime AFM Cantilever Chip AFM Instrument Head Laser Beam Path Cantilever Deflection

Scanning probe microscope Laser Beam Vibrating Cantilever PS/PEO AFM image µm (large ) Surface AFM, STM, MFM, others

STM Image of Nickel Atoms

Pushing Atoms Around STM

"Optical Lever" x2 x1 y1 y2 For example, if the laser pointer is 2" long, and the wall is 17' (204") away, Motion amplified by 100 times!

"Optical Lever" for Profilometry laser . cantilever

"Optical Lever" for Profilometry Long light path and a short cantilever gives large amplification laser . cantilever