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What if we could assemble the basic ingredients of life the way nature does it, atom by atom and molecule by molecule? Feynman’s Talk, 1959, Caltech “What I want to talk about is the problem of manipulating and controlling things on a small scale.” “Why cannot we write the entire 24 volumes of the Encyclopedia Brittanica on the head of a pin?” × 25,000 = head of a pin = 1/16 inches across All the pages of the Encyclopedia Brittanica 1/120 inch= diameter of a dot in the Encyclopedia ÷ resolving power of a human eye 80 Angstroms (32 atoms in ordinary metal) 25,000 = Feynman’s Talk, 1959, Caltech “What are the limitations as to how small a thing has to be before you can no longer mold it? How many times when you are working on something frustratingly tiny like your wife's wrist watch, have you said to yourself, ``If I could only train an ant to do this!'' What I would like to suggest is the possibility of training an ant to train a mite to do this” Feynman’s Talk, 1959, Caltech “A friend of mine (Albert R. Hibbs) suggests a very interesting possibility for relatively small machines. He says that, although it is a very wild idea, it would be interesting in surgery if you could swallow the surgeon. You put the mechanical surgeon inside the blood vessel and it goes into the heart and ``looks'' around. It finds out which valve is the faulty one and takes a little knife and slices it out.” •Electron-Beam Fabrication •Molecular Beam Epitaxy •Nanoimprint Lithography •Spin Electronics •Microelectromechanical Systems (MEMS) •Nano-Technology first used by N.Taniguchi (1974) •Nanotechnology became popularized after K.E. Drexler’s book “Engines of Creation” in 1986. What does Nanotechnology mean? •“Nano” derives from the greek word for dwarf. •It represents a billionth of a unit. 1nm = billionth of a meter = 10-9 m How small is a nanometer? Nanotechonology: Real or just a buzz word? •Some nanotechnology isn’t nano •Nanotechnology, in some cases is not technology •Nanotechnology is a new word but not an entirely new field. Why not an entire new field? •Nano-sized carbon particles used in tires for about 100 years •Vaccines, which often consist of one or more proteins with nanoscale dimensions •Chemical catalysts, such as those turning cheap graphite into synthetic diamond. •Photosynthesis (natural nanotechnology) Photosynthesis What is special about Nanotechnology? •Broad Interdisciplinary field •Borderland between the atoms and the macroworld •Human control at the finest scale Nanotechnology: Is it fiction? From Fiction to Reality: Skeptical Questions •Can macroscopic objects be built from molecular scale processes? •Are molecular objects stable? •What about quantum effects? •What about Brownian effects? •What about high-energy radiation? •What about friction and wear? Nanotechnology does not violate any physical law. Approaches to Nanotechnology •Top-Down Approach •Bottom-Up Approach Top-Down Approach 1/4 Machine Shop 1/4 Reduced-Scaled Machine Shop MicroElectro-Mechanical Systems (MEMS) MicroElectro-Mechanical Systems (MEMS) MicroElectro-Mechanical Systems (MEMS) Microcar by Nippondenso Co. Body: 4 mm long, 1.8 mm wide and 1.8 mm high Tires: 0.7 mm diameter, 0.17 mm wide Licence Plate: 10 micron thick Top-Down Nanofabrication Top-Down Nanofabrication Electron Beam Lithography •Pattern written in a polymer film with a beam of electrons •No blurring of features •Very expensive and time-consuming X-ray Lithography •Wavelength = 0.1-10 nm, no blurring •Conventional lenses do not focus X-rays •Radiation damage of materials Top-Down Nanofabrication Bottom-Up Nanofabrication •Supramolecular and molecular chemistry •Scanning probes •Biotechnology Supramolecular Chemistry (Chemistry of non-covalent bonds) Self-Assembly demands: •Well-defined adhesion between molecules •Shape and size complementarity •Large contact areas •Strong overall binding Advantages of Self-Assembly •It carries by itself the most difficult steps in nanofabrication, i.e., the smallest steps •Can incorporate biological structures directly as components in the final systems. •Because target structures are thermodynamically stable, it produces structures that are relatively defect-free and self-healing. Self-Assembly Carbon Nanotubes Growth of C nanotubes CVD Synthesis Self-Assembly Carbon Nanotubes Structure of C Nanotubes Single Walled Nanotube Multi Walled Nanotube Gears of C Nanotubes 70 GHz Gears of C Nanotubes >150 GHz Rack/Pinion C Nanotubes Quantum Dots Bottom-Up Nanofabrication •Supramolecular and molecular chemistry •Scanning probes •Biotechnology Scanning Probes Manipulation of Atoms by SP Atomic Writing by SP Bottom-Up Nanofabrication •Supramolecular and molecular chemistry •Scanning probes •Biotechnology Drexler wrote: “The ability to design protein molecules will open a path to the fabrication of devices to complex atomic specfications” Biotechnology Biological Molecular Machine: Ribosome 1 large RNA 1 small RNA 33 proteins 1 RNA 21 proteins Ribosome as an assembler Abalone Abalone Shell: Self Assembly Applications •Nanodevices •Nanoelectronics •Nanomedicine Nanodevices Single-Electron Transistor Challenges for Nanodevices •Communication between the macroworld and the nanoworld. •Surfaces (high surface/volume ratios) Nanoelectronics •1st level of organization: transistors •2nd level of organization: interconnects Molecular Transistors C Nanotube Interconnects •Wire interconnect delays account for half of chip signal delays •Copper interconnects being used for 130nm devices •Microelectronic devices being scaled down from 130nm to 50nm generation •Copper interconnects not suitable for 50nm devices C Nanotube Interconnects First level interconnect C Nanotube Interconnects Single wall nanotube ~ 1.4 nm Jc = 109 A/cm2 ts ~ 30GPa K ~ 2000W/mK DNA Computing Nanomedicine Magnetic Nanoparticles S N Nanomedicine Nanomedicine Nanotechnology: A Look to the Future Estimated government sponsored R&D in $millions-year Fiscal Year 1997 2000 2001 2002 Europe 126 200 225 400 Japan 120 245 465 650 USA 116 270 422 604 Others 70 110 380 500 Total 432 825 1502 2154 Nanotechnology R&D at the Department of Defense (Funding:$140 M) •Chem-bio warfare defense: sensors with improved detection sensitivity and selectivity, decontamination. •Protective Armors for the warrior: Strong, light-weight bullets-stopping armor •Reduction in weight of warfighting equipment:Miniaturization of sensors,computers, comm devices, and power supplies. •High performance platforms and weapons: Greater stealth, higher strength light-weight materials and structures. •Energy and Energetic Materials: Energetic nano-particles for fast release explosives and slow release propellants. •Uninhabited vehicles: Miniaturization to reduce payload. Nanotechnology R&D at the Department of Energy (Funding:$100 M) •Fossil energy: materials performing under extreme temperatures and pressures, nanostructured catalysts for optimal petroleum refining. •Energy efficiency: High-performance magnets, nanofluids, smart Materials, strong, tough, ductile materials. •Renewable energy: Energy storage systems, nanostructured materials for hydrogen storage. •Nuclear Energy: Radiation tolerant materials, nanostructures that lower waste disposal costs. Nanotechnology R&D at NASA (Funding:$46 M) •Nanostructured Materials: High strength/mass ratio, smart materials, •Nanoelectronics: Space qualified data storage, self-healing systems for extended missions. •Sensors: Nanodevices, NEMS flight system. •Nanoscience: Self-assembly and processing in space, space-induced health effects. Nanotechnology R&D at NIH (Funding:$40 M) •Detection of Diseases •Implants to replace worn or damaged body parts. •Delivery of therapeutics •Nanoimaging •Cell Biology •Nano-motors •Cellular implants