Overview of Nanoscience and Overview of Nanoscience and NanotechnologyNanotechnology
OOğuz Gülserenğuz Gülseren
Al
Al2O3
Barrier Layer
Pores
×× 300300
×× 300300
A pictorial definition of NanoA pictorial definition of Nano
Aphid
× 100
Paramecium × 100
Tina (Weatherby) CarvalhoBio Images by:
× 100
Electronics, circa 1985Electronics, circa 1985
40 nanometers40 nanometers
× 1000
Electronics, circa 2010Electronics, circa 2010
Electronics, circa 1985Electronics, circa 1985
Electronics, circa 2010Electronics, circa 2010
Electronics, circa 2040Electronics, circa 2040
X 100
1 nm diameter 1 nm diameter molecular wires molecular wires
The Incredible The Incredible TininessTininess of of NanoNano
Billions of nanometers
A two meter tall male is two billion nanometers.
A millionnanometers
The pinhead sized patch of this thumb is a million
nanometers across.
Thousands ofnanometers
Biological cells have diameters in the range of thousands of nanometers.
NanometersTen shoulder-to-shoulder hydrogen atoms span 1
nanometer. DNA molecules are about 2.5
nanometers wide.
Less than ananometer
Individual atoms are up to a few tenths of a
nanometer in diameter.
A human hair is approximately 100,000 nm.
nano = dwarf (Greek) nano = dwarf (Greek)
NaCl-(001) island on a Cu(111) surface
protonatom
virus
radius of the earth
earth-sun
radius ofgalaxies
NanoNano the lengths scales ofnano physics....
- atoms- molecules- clusters- solids
meter
Ångstrom
.....are the lengths scales of life
- atoms- molecules- cells- organisms
Nano = 10Nano = 10--99
1 nm = 101 nm = 10--9 9 mm
1 m 10 Å: 1,000,000,000
The visionThe visionThe classic talk: “There's Plenty of The classic talk: “There's Plenty of Room at the Bottom” Room at the Bottom” Richard Feynman,Richard Feynman, December 29, 1959. The December 29, 1959. The annual meeting of the American Physical Society annual meeting of the American Physical Society at Caltechat Caltech
• “Why cannot we write the entire 24 volumes of the Encyclopedia Britannica on the head of a pin?”
• “Biology is not simply writing information; it is doing something about it. A biological system can be exceedingly small.”
• “I want to build a billion tiny factories, models of each other, which are manufacturing simultaneously, drilling holes, stamping parts, and so on.”
World’s First Tiniest MotorWorld’s First Tiniest Motor
Richard Feynman viewing the micromotor built by William McLellan (left) who won the challenge to build the first motor smaller than 1/64th of an inch (left). The motor photographed under an optical microscope (right).
Picture credit: Caltech Archives
Red Herring, May 2002
Commonality: Railroad, auto, computer, nanotechall are enabling technologies
1970 1975 1980 1985 1990 1995 2000 2005 2010103
104
105
106
107
108
109Transistors per chip
Year
80786PentiumPro
Pentium80486
8038680286
8086
80804004
?
micro nano
Moore‘s LawMoore‘s Law
1985 1990 1995 2000 2010 2015 202010-1
100
101
102
103
104Electrons per device
2005Year
(Transistors per chip)
(16M)(4M)
(256M)(1G)
(4G)(16G)
(64M)
micro nano
Vanishing electronsVanishing electrons
PastShared computing thousands of people sharing a mainframe computer
PresentPersonal computing
FutureUbiquitous computing thousands of computers sharing eachand everyone of us; computers embedded in walls, chairs, clothing,light switches, cars….; characterized by the connection of things inthe world with computation.
The incredible shrinking disk drive
1956 IBM Ramac 305 vs. 2000 IBM Microdrive5 MB 1 GB50 x 24” dia. disks 1 x 1” diskweighs “a ton” < 1 oz.$50,000 $500
Nanotechnology R&D Funding in the USANanotechnology R&D Funding in the USA
Fiscal yearFiscal year 20002000 2001 20022001 2002 20032003(all in million $)(all in million $)
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
National Science FoundationNational Science Foundation 9797 150150 199 199 221221Department of DefenseDepartment of Defense 7070 125125 180180 201201Department of EnergyDepartment of Energy 5858 8888 91.1 139.391.1 139.3National Institutes of Health National Institutes of Health 3232 39.639.6 40.840.8 43.2 43.2 NASANASA 55 2222 46 51 46 51 NISTNIST 88 33.433.4 37.6 43.8 37.6 43.8 Environmental Protection Agency Environmental Protection Agency -- 5.85.8 55 55Depart. of Transportation/FAA Depart. of Transportation/FAA -- 22 22Department of Agriculture Department of Agriculture -- 1.51.5 1.51.5 2.52.5Department of Justice Department of Justice -- 1.41.4 1.4 1.41.4 1.4TOTALTOTAL 270.0 270.0 466.7466.7 604.4 710.2 604.4 710.2
Other NNI participants are: DOC, DOS, DOTreas, NOAA, NRCOther NNI participants are: DOC, DOS, DOTreas, NOAA, NRC, USG, USG
M.C. Roco, NSF, 4/30/02
0
500
1000
1500
2000
2500
1997 1998 1999 2000 2001 2002
mill
ions
$ /
year
W. EuropeJapanUSAOthersTotal
Senate Briefing, May 24, 2001 (M.C. Roco), updated on February 5, 2002
• U.S. begins FY in October, six month before EU & Japan in March/April• U.S. does not have a commanding lead as it was for other S&T megatrends
(such as BIO, IT, space exploration, nuclear)
Context Context –– Nanotechnology in the WorldNanotechnology in the WorldGovernment investments 1997Government investments 1997--20022002
Note:
Nanostructures:Nanostructures:
a.a. Contain a Contain a countablecountable number of number of atomsatoms
b.b. Suites for Suites for atomic levelatomic level detailed detailed engineeringengineering
c.c. Provide access to realms of Provide access to realms of quantum behaviorquantum behaviorthat is not observed in larger (even 0.1 µm) that is not observed in larger (even 0.1 µm) structuresstructures
d.d. Combine Combine small sizesmall size, , complexcomplex organizational organizational patternspatterns, potential for very , potential for very high packinghigh packing densities, densities, strong lateral strong lateral interactionsinteractions and high ratios of and high ratios of surface area to volume.surface area to volume.
SoSo…….What are Nanoscience and Nanotechnology?.What are Nanoscience and Nanotechnology?
The ability to observe, The ability to observe, measure, predict and measure, predict and construct construct —— on the scale on the scale of atoms and moleculesof atoms and moleculesand and exploitexploit the novel the novel properties found at that properties found at that scale.scale.
……and beyond the nice definitions and beyond the nice definitions ……What it really isWhat it really is……..
• Examples- Carbon Nanotubes- Proteins, DNA- Single electron transistors
• Not just size reduction but phenomena intrinsic to nanoscale- Size confinement- Dominance of interfacial phenomena- Quantum mechanics
• New behavior at nanoscale is not necessarily predictable from what we know at macroscales.
AFM Image of DNA
Source: Nanoscale Materials in Chemistry, Wiley, 2001
The melting point decreases dramatically as the particle size gets below 5 nm
Source: Nanoscale Materials in Chemistry, Wiley, 2001
Nanostructures (< 30 nm) have become an exciting research Nanostructures (< 30 nm) have become an exciting research fieldfield–– New quantum phenomena occur at this length scaleNew quantum phenomena occur at this length scale–– New structure New structure –– property relations are expectedproperty relations are expected–– Promising applications are expected in optics, electronics, Promising applications are expected in optics, electronics,
thermoelectric, magnetic storage, NEMS (nanothermoelectric, magnetic storage, NEMS (nano--electroelectro--mechanical systems)mechanical systems)
LowLow--dimensional systems are realized by creating dimensional systems are realized by creating nanostructures that are quantum confined in one or more nanostructures that are quantum confined in one or more directions and directions and exhibit properties different from their 3D exhibit properties different from their 3D counterpartscounterparts
3DBulk Semiconductor
2DQuantum Well
1DQuantum Wire
0DQuantum Dot
E
D. O
. S.
D. O
. S.
D. O
. S.
D. O
. S.
E E E
• For semiconductors such as ZnO, CdS, and Si, the bandgapchanges with size
- Bandgap is the energy needed to promote an electron from the valence band to the conduction band
- When the bandgaps lie in the visible spectrum, changing bandgap with size means a change in color
• For magnetic materials such as Fe, Co, Ni, Fe3O4, etc., magnetic properties are size dependent
- The ‘coercive force’ (or magnetic memory) needed to reverse an internal magnetic field within the particle is size dependent
- The strength of a particle’s internal magnetic field can be size dependent
Motivation towards NanotechnologyMotivation towards Nanotechnology
Nanometer scale physics and chemistry might Nanometer scale physics and chemistry might lead directly to:lead directly to:
Smaller and faster electronic devices.Smaller and faster electronic devices.Device miniaturization by reducing their physical sizesDevice miniaturization by reducing their physical sizesExploiting enhanced surface effects by increased surface/volume Exploiting enhanced surface effects by increased surface/volume ratio (e.g. catalysts)ratio (e.g. catalysts)Stronger and lighter materials with more functionality.Stronger and lighter materials with more functionality.Utilization of biological objects in inorganic nanostructures foUtilization of biological objects in inorganic nanostructures for r various sensors and novel functionsvarious sensors and novel functionsSupply instrumentation to speed gene sequencing and chemical Supply instrumentation to speed gene sequencing and chemical agents to detect tumors.agents to detect tumors.Store Library of Congress on a device the size of a sugar cube.Store Library of Congress on a device the size of a sugar cube.Exciting new science discoveries because the properties of nanoExciting new science discoveries because the properties of nano--materials are expected to be different from their bulk counterpamaterials are expected to be different from their bulk counterparts.rts.Novel phenomena in lowNovel phenomena in low--dimensional structuresdimensional structuresDirect observation of physics laws in nanostructuresDirect observation of physics laws in nanostructures
““NanoNano” Timeline” Timeline19051905: Einstein published a paper that estimated the : Einstein published a paper that estimated the diameter of a sugar molecule as 1 nm.diameter of a sugar molecule as 1 nm.19591959: Richard Feynman’s famed talk.: Richard Feynman’s famed talk.19811981: : BinnigBinnig and Rohrer created the STM to image and Rohrer created the STM to image individual atoms.individual atoms.19851985: Curl, : Curl, KrotoKroto, Smalley discovered C, Smalley discovered C6060..19931993: : IijimaIijima, Bethune discovered single wall carbon , Bethune discovered single wall carbon nanotubes.nanotubes.19981998: : CeesCees Dekker’sDekker’s group created a TUBEFET.group created a TUBEFET.20012001: Nanowire : Nanowire ZnOZnO laserlaser20022002: : SuperlatticeSuperlattice NanowiresNanowires
(Schmidt et. al.)
ClustersClusters
(a) Bi Nanowire (b) Bi Nanotube (c) Bi Atomic Line
Various Nanostructures can occur in 1DEach have different structure/properties
Selectivity is therefore important
K. MikiETL,Japan
Peidong YangUC Berkeley
Dresselhaus Group(MIT)
TEM of CdSe quantum rods, with average size 25*4 nm.
(Banin et. al.)
NanoparticlesNanoparticles
TEM of CdSe quantum rods, with average size 25*4 nm.
Membrane ProteinsMembrane Proteins
Examples of Quantum WiresExamples of Quantum Wires
Nanotube
(Dekker et. al.)The Fullerenes:Nanoscale control
over materials properties
Nobel Prize in Chemistry, 1996
Nanotubes
DNA
(Cohen et. al.)
3.4 Å
34 Å
Example of DNAExample of DNA--Nanotube hybridNanotube hybrid
(Dekker et. al.)
A scanning tunneling microscope image of a Single-Walled Carbon NanotubeA symbol of the origins of Nanoscience & Nanotechnology
Unique Properties of Carbon Unique Properties of Carbon NanotubesNanotubes
• Size: Nanostructures with dimensions of ~1 nm diameter (~20 atoms around the cylinder)
• Electronic Properties: Can be either metallic or semiconducting depending on the diameter or orientation of the hexagons
• Mechanical: Very high strength and modulus. Good properties on compression and extension
• Heat pipe and electromagnetic pipe• Single nanotube spectroscopy yields structure• Many applications are being attempted worldwide
Graphene sheet SWNT
Roll up
2 2
1 21
( , )3tan
2
t
h
L ad n nm mC na ma n m
mn m
π π
θ −
= = + += + ≡ = +
(4,2)
Rolling up graphene layer
0θ = °
0 30θ< < °
30θ = °armchair
zigzag
chiral
Nanotubes
(n-m) = 3q metallic(n-m) = 3q ±1 semiconducting
The Fullerenes:Nanoscale control over materials propertiesNobel Prize in Chemistry, 1996
The Scanning Tunneling Microscope: Resolving the atomic worldNobel Prize in Physics, 1988
The Development of Technological Means The Development of Technological Means and Computational Power Sufficient for and Computational Power Sufficient for Visualizing and operating in the NanoVisualizing and operating in the Nano--WorldWorld
Main Tools for Nano:Main Tools for Nano:
1.1. ObservationObservation::a)a) SEM/TEM (optical)SEM/TEM (optical)b)b) SPMSPM
2.2. ConstructionConstruction::a)a) EE--beam/optical Lithographybeam/optical Lithographyb)b) SPM LithographySPM Lithographyc)c) Self assemblySelf assemblyd)d) ChemistryChemistry
There are two ways to build a house…...
TopTop--downdown
BottomBottom--upup
A “Nano ToolA “Nano Tool--box”box”
To fabricate/probe nanostructuresTo fabricate/probe nanostructures
NanofabricationNanofabrication
Top-down Method
- create nanostructures out of macrostructures
Bottom-up Method
- self assembly of atoms or molecules into nanostructures
Scanning Tunneling Microscope (STM)Scanning Tunneling Microscope (STM)
Sample
Piezo
Electronics(Current+Feedback)
Computer(Control)
Matrix ofheights(Image)
Tip
I(V) ~ Ve-(ks)
Tunneling between a sharp tip and conducting surface.Piezo enables xy and z movement.Working mode: constant current.The feedback voltage Vz(x,y) is translated to height (topographic) information.
STM ImagesSTM Images
Graphite – atomic resolution: Supercoiled DNA
Atomic Force Microscope ( AFM) PrincipleAtomic Force Microscope ( AFM) Principle
AFM ImagesAFM Images
Magnetic bits of a zip disk G4-DNA
100nm10µm
DNA-NanotubeNanotube between
electrodes
AFM nanographyAFM nanographyatomic force microscope
manipulate a surfaceby- applying a local electric field
- local oxidation
(Avouris et al. IBM)
Carbon Nanotube Manipulation
AFM Scanning
Lowering the tip and pushing
VDW forces hold the CNT
……For exampleFor example……..
(Eigler et. al.)
Directions of development in Nano:Directions of development in Nano:
1.1. NanoelectronicsNanoelectronics2.2. NanoNano--mechanics mechanics
(MEMS/NEMS)(MEMS/NEMS)3.3. NanoNano--bio(techno)logybio(techno)logy4.4. NanoNano--medicinemedicine
Nanotube circuits Nanotube circuits ((CeesCees Science cover)Science cover)
(Avouris et al. IBM)
A Field-Effect Transistor Made from a Single-Wall Carbon Nanotube
(Avouris et al. IBM)AFM Oxidation
61 % Humidity 14 % Humidity
Applications for NanotubesApplications for NanotubesScanning tips and Scanning tips and
ElectronicsElectronicsSTM/AFM tipsSTM/AFM tipsDirect Analysis of DNADirect Analysis of DNASemiconductor devicesSemiconductor devicesField EmittersField Emitters
S.J. Tans et al. Nature, 393, 49 (1998)
AFM image of Immunoglobulin G resolved by nanotube tips
Field Emitter
Transistor
Imaging biological molecules
New Materials
Fullerene C60 inside nanotubes
Potential for high hydrogen Potential for high hydrogen capacity capacity relativerelative to other to other carbon structures.carbon structures.–– single wall structuresingle wall structure–– multiple adsorption sitesmultiple adsorption sites–– high packing density if alignedhigh packing density if aligned–– 8 wt% for pure materials at 80K 8 wt% for pure materials at 80K
(Caltech/JPL)(Caltech/JPL)–– 7 wt% at room temperature (NREL)7 wt% at room temperature (NREL)
Issues:Issues:–– wide variability in resultswide variability in results–– processing uncertaintiesprocessing uncertainties–– synthesis of large quantities with synthesis of large quantities with
high purity at low costhigh purity at low cost–– Small amount of energy required for Small amount of energy required for
adsorption and adsorption and desorptiondesorption
B. Pradhan, et al 2001
L. Schlapbach, A. Zuttel 2001
Carbon Nanotubes for Hydrogen storageCarbon Nanotubes for Hydrogen storage
Reproducibility is a key issue for carbon nanotubes.
Organic Nanostructures: The Electrical Organic Nanostructures: The Electrical Conductivity of a Single Molecule (breakConductivity of a Single Molecule (break--junctions)junctions)
(Reed et al. 1997)
Resonant Tunneling Devices in Nanoelectronics
4 bit 2 GHz analog-to-digital converter, 3 GHz (40 dB spur-free dynamic range) clocked quantizer, 3 GHz sample and hold (55 dB linearity), clock circuits, shift registers, and ultralow power SRAM (50 nW/bit)
(Seabaugh 1998)
(Avouris et al. IBM)Theory of CNTTwisting angle
effect on energy band-gap
Bending effect of on CNT Electronic Structure
(A) Streptavidin molecules bind to a silicon nanowire functionalized with biotin.The binding of streptavidin to biotin causes the nanowire to change its resistance. (B)The conductance of a biotin-modified silicon nanowire exposed to streptavidinin a buffer solution (regions 1 and 3) and with the introduction of a solution of antibiotin monoclonal antibody : (region 2) (Cui et al., 2001).
Si Nanowire Sensor
biotin
*Direct read-out of binding of antigen-antibody.
*Multiple sensors can be used for laboratory test
Quantum Confinement Produces New Quantum Confinement Produces New Materials ClassesMaterials Classes
• Bi – Group V element– Semimetal in bulk form– The conduction band (L-electron)
overlaps with the valence band (T-hole) by 38 meV
Decreasing wire diameter
Semimetal Semiconductor
• Bi nanowire– Semimetal-semiconductor
transition at a wire diameter about 50 nm due to quantum confinement effects
SemimetalSemimetal--Semiconductor TransitionSemiconductor TransitionWe utilize novel properties in applications
Tunable Tunable BandgapBandgap in Nanowiresin Nanowires
InP nanowire
diameter ↓
energy ↑
M. S. Gudiksen et al., J. Phys. Chem B 106, 4036 (2002)
With same material luminescence devices with different emission frequencies can be made
NanoNano--Lasers using Lasers using ZnOZnONanowiresNanowires
ZnO nanowires grown by VLS method.
Emission spectrum from ZnO nanowires.Peidong Yang et al
Wavelength (nm)370 380 390 400
Inte
nsity
(a.u
.)
Nanowire UV Nanolaser
UV Laser Output
Excitation
SuperlatticeSuperlattice Nanowires for Nanowires for
Thermoelectric ApplicationsThermoelectric Applications
Superlattice (2D) Nanowire (1D)
Superlattice Nanowire (0D)
phonon
e- Electron transmitting
Phonon blocking
Y.-M. Lin in Dresselhaus MITgroup
Published in Nature
• Quantum Computing- Takes advantage of quantum
mechanics instead of being limited by it
- Digital bit stores info. in the form of ‘0’ and ‘1’; qubitmay be in a superposition state of
‘0’ and ‘1’ representing both valuessimultaneously until a measurement is
made- A sequence of N digital bits can
represent one number between 0 and 2N-1; N qubits
can represent all 2N numbers simultaneously
• Carbon nanotube transistor by IBM and Delft University
• Molecular electronics: Fabrication of logic gatesfrom molecular switches using rotaxanemolecules
• Defect tolerant architecture, TERAMAC computerby HP architectural solution to theproblem of defects in future molecular electronics
• Expanding ability to characterize genetic makeup willrevolutionize the specificity of diagnostics and therapeutics
- Nanodevices can make gene sequencing more efficient
• Effective and less expensive health care using remote and in-vivo devices
• New formulations and routes for drug delivery, optimal drug usage
• More durable, rejection-resistant artificial tissues and organs
• Sensors for early detection and prevention
Nanotube-basedbiosensor forcancer diagnostics
Optoelectrical characterization of a crossed nanowire junction formed between65-nm n-type and 68-nm p-type InP nanowires. (a) Electroluminescence (EL) image of thelight emitted from a forward-biased nanowire p-n junction at 2.5 V. Inset, photoluminescence(PL) image of the junction. (b) EL intensity as a function of operation voltage. Inset, theSEM image and the I-V characteristics of the junction (Duan et al., 2001). The scale bar inthe inset is 5 microns.
I-VPLEL
Luminescence from Nanowire Junctions
*Light emission from nanowire junctions
SelfSelf--Assembled Assembled NanoporesNanopores in Aluminain Aluminafor growing nanowires/nanotubesfor growing nanowires/nanotubes
ApplicationsApplications–– Templates for ordered Templates for ordered
arrays of nanowires and arrays of nanowires and nanotubesnanotubes
–– 2D photonic crystal2D photonic crystal–– High density magnetic High density magnetic
storage mediastorage media
Al
Al2O3
Barrier Layer
Pores
Free-standing wires
Nanowire array
SEM image of the surface of an anodic alumina template with self-assembled nanopore structure
Template Dissolution
Nanowire Array (Charles Nanowire Array (Charles LieberLieber))
Addressable array for logic functions
A Commercial IBM Giant MagnetoresistanceRead Head
‘Self-healing plastic’ by Prof. Scott White (U. of Illinois) Feb. 15, 2001, Issue of Nature
• Plastic components break because of mechanical or thermalfatigue. Small cracks large cracks catastrophic failure.‘Self-healing’ is a way of repairing these cracks without humanintervention.
• Self-healing plastics have small capsules that release a healingagent when a crack forms. The agent travels to the crack through capillaries similar to blood flow to a wound.
• Polymerization is initiated when the agent comes into contactwith a catalyst embedded in the plastic. The chemical reactionforms a polymer to repair the broken edges of the plastic. New bond is complete in an hour at room temperature.
Quantum Information ScienceQuantum Information Science Nanoscale MaterialsNanoscale Materials
Biology & HealthcareBiology & Healthcare
Molecular ElectronicsMolecular Electronics
BIG future for NANO
• If nano research is the Mt. Everest, we have barely reached the base camp!(Charles Lieber)
• If Einstein were looking for a career path today, his advisor would tell him to think small: “Nanotech, Albert, nanotech” (Gary Stix)