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From Nanoscience to Nanotechnology with Photons

Zahid HussainDivision Deputy for Scientific Support

Advanced Light Source, Lawrence Berkeley National Laboratory

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OutlineOutlineOutline

Why and How ?

• The Big Picture• What is synchrotron radiation and why ?

• What is emergent phenomena ?

• What kind of tools are necessary for understanding nano systems ?

• Road from science to technology (examples).

Understanding complex phenomena require sharper and sharper toolUnderstanding complex phenomena require sharper and sharper tools s

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The Big Picture

Science Needs & Grand Challenges

The Big Picture

Science Needs & Grand Challenges

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Many reports (USA:BES & National Labs) science needs for new light sources

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Five Grand Challenges for Scienceand the Imagination for BES

• How do we control materials and processes at the level of electrons ?

• How do we design and perfect synthesis of revolutionary new forms of matter with tailored properties ?

• How do remarkable properties of matter emerge from complex correlations of atomic and electronic constituents and how can we control these properties ?

• How can we master energy and information on the nanoscaleto create new technologies with capabilities rivaling those of living systems ?

• How do we characterize and control matter away—especially very far away—from equilibrium ?

♣

♣

♣

♣

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Overall Challenge: Making the Leap from Observation Science to Control Science

Designing materials to have the properties we require the Designing materials to have the properties we require the ability to see ability to see functionalityfunctionality at the relevant at the relevant time time (down to fs),(down to fs),Length Length (down to nm) (down to nm) & & energy energy (down to meV)(down to meV)scales.scales.

We will need to develop & disseminate new toolscapable of viewing the inner workings of matter — at the level of electrons, spins, atoms or molecules.

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Free Electron Laser

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Why X-Rays ?

Not neutrons or electrons

Why X-Rays ?

Not neutrons or electrons

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Electrons

Why X-Rays ( & not neutrons or electrons ) ?

Optical

Tunable x-rays offer variable interaction cross section

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WHAT DOESWHAT DOES SRSR BRIGHTNESSBRIGHTNESS BUY YOU?BUY YOU?

Very High EnergyResolution

Nano-meterSpatialResolution Coherence

20 μmTomographic reconstruction of

Saccharomyces cerevisiae(yeast).

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Nanostructures

Adopted from: Franz Himpsel, CMMP ‘07

PhotonEnergy

Wave-length

10eV 100eV 1keV 10keV

10nm100nm 1nm 1Å

ValenceElectrons Core Electrons

LithographyProtein

Crystallo-graphy

Proteomics

Science with Light Sources

Spectroscopy Structure

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Science with Synchrotron RadiationScience with Synchrotron RadiationScience with Synchrotron Radiation

Applications in the field of:• Nano science• complex materials (strongly correlated electron systems such

as high Tc material, CMR)• Magnetism (dynamical studies of magnetism)• Energy research (combustion dynamics, solar energy,

fuel cell, Hydrogen storage)• Environment Science• Catalysis, corrosion (kinetics of reactions at surfaces)• Biological systems (structure of proteins and its function)• Semiconductor devices

Many synchrotron radiation techniques may be applicable under in-situ conditions where the sample is kept under natural conditions and/or under extreme environment such as high pressure.

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What are experimental tools with x-rays ?

Many and still growing

What are experimental tools with x-rays ?

Many and still growing

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Spectroscopy Scattering Imaging01 Low-Energy Spectroscopy 05 Hard X-Ray Diffraction 09 Hard X-Ray Imaging02 Soft X-Ray Spectroscopy 06 Macromolecular

Crystallography10 Soft X-Ray Imaging

03 Hard X-Ray Spectroscopy 07 Hard X-Ray Scattering 11 Infrared Imaging04 Optics/Calibration/Metrology 08 Soft X-Ray Scattering 12 Lithography

Techniques of SR

The fundamental parameters necessary for perception of physical world:• Energy (spectroscopy, state of matter)• Momentum (scattering)• Position (imaging, spatial distribution)• Time (dynamics)

numerous techniques of SR

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Opportunities for nanoscience with soft x-rays @ ALS

1. Spectroscopy (In-Situ, real time)Absorption/Emission Spectroscopy (photon-in photon-out, bulk

sensitivity, mag/elctric field)Photoemission Spectroscopy (photon-in electron-out, surface

sensitivity, upto 10 torr)

2. Microscopy (sometime combined with spectroscopy)Scanning Transmission Microscope (STXM; Res ~25nm)Transmission Imaging Microscope (XM1/2; Res ~15 nm)Photoemission electron microscope (PEEMII/III; Res ~5-50nm) Lensless diffractive imaging (3D images, Res ~5-10nm)

3. ScatteringResonant Scattering (~100-1000 times higher cross section)Resonant Inelastic Scattering (res ~3-4meV @ Mn/Cu 3p edges) Coherent (dynamic) Scattering (time resolution msec to nanosec)Small and Wide Angle Scattering (SAXS/WAXS, soft x-rays

provide unique capabilities)

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Small is differentSmall is fastEmergent Phenomena in the Nanoscale:Phenomena which are not the properties of the individual elementary components BUT of the assembly of such components

Courtesy: Uzi Landman, Georgia Institute of Technology

What is Nanoscience ?What is Nanoscience ?

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SpectroscopySpectroscopySpectroscopy

Quantum confinement (properties different than bulk/constituents)

Chemical Bonding (chemical reactivity)

Electronic Structure (understanding complexity)

Bashir DabbousiPhD Thesis: 1997US Patent 2005

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Soft-x-ray Absorption/Emission Spectroscopy

hν

hν'

UnoccupiedMOs

OccupiedMOs

O 1s

Inte

nsity

(a.u

)540535530525520515

Energy (eV)

XASXES4a1

2b2

3a1

1b2

1b1

Excitation process: < 10-15 sDe-excitation: 10-15 s

Band Gap

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Quantum Confinement Effects in Semiconductor Nanocrystals (NCs)

Phot

olum

ines

cenc

e/ar

b. u

nits

3.02.0Energy (eV)

Absorbance/arb. units

37 Å

45 Å

60 Å

85 Å

Semiconductor nanocrystals (e.g., ZnSe/‘Quantum dots’

• Optoelectronic behavior explained in terms of quantum confinement effects: Particle in a Box

• Unique, size-dependent, optical and electronic properties• Diverse range of potential technological applications

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Quantum-confinement effects and particle-particle interactions in Ge & Si nanocrystals

C. Bostedt et al. APL 84, 4056 (2004) — LLNL PRTC. Bostedt et al. APL 85, 5334 (2004)

• Ge nanoparticles condensed out of the gas-phase

• Particle-size determined post-situ by AFM

• Blue-shift of Ge L-edge correlated with decreasing cluster size

• Stronger CB confinement effects observed in Ge than in Si nanoparticles.

•Tuning of band gap!

sub-ML multilayer

Atomic force microscopeAbsorption Spectra

Conduction band shift vs particle size

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Surface Reconstructions in Nanodiamonds(extracted from explosives)

J.-Y. Raty, G. Galli, C. Bostedt, T.W. Buuren & L.J. Terminello,PRL 90, 4056 (2003) — LLNL PRT

• Pre-edge Carbon K-edge structures observed in diamond clusters different from bulk diamond.

• Fullerene-like reconstructions determined at surfaces of diamond clusters by ab initiocalculations compatible with pre-edge XAS

C147 (≈1.2 nm) C275 (≈1.4 nm)

Emission Absorption

Need of theory

Core – Diamond; Surface – buckyballs

(sp2/sp3)

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“Gluing Up” High Energy Capacity Batteries – A Closed Loop!

LUMOX-ray Spectroscopy

ElectronicStates

0

1000

2000

3000

0 5 10 15

Spec

ific

cap

acity

(mAh

/g)

Cycle no.

Si/PVDF/ABSi/PFSi/PFFOSi/PFPFOMB

C

Performance

• 10 times higher energy capacity than Graphite based Li-ion battery electrodes

• Best available full capacity cycling results from an composite electrode

• Photon-in-photon-out X-ray spectroscopy shows directly WHY it

works and HOW to optimize

372State-of-the-art Graphite

32

111 2

Synthesis

Patent Pending

--- G. Liu etc. at EETD & W.L. Yang etc. at ALS

12

3 1

2

3

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Analysis hints at solar energy alternativesSilicon alternatives in high demand

FeSFeS22, Fool, Fool’’s Golds Gold

Cyrus Wadia, Dan Kammen, Paul Alivisatos

Consists of Fe+2 and (S2)-2

Space Group Pa3(Th6)

Local symmetry around Fe+2 Oh to C3iLattice constant a=5.416 Ǻ

X-ray diffraction

XPS

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Bandgap Measurement

Cyrus Wadia, Yue Wu, Sheraz Gul, Steven K. Volkman, Jinghua Guo, and A. Paul Alivisatos, Chenimistry of Materials, June 2009indirect bandgap

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Einstein’sequation

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(Elemental identity)(Quantitative)(Chemical state)

-101

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C 1s photoelectron spectra of propyne (res: SR~30meV,

lab source ~ 0.5 eV (dashed))

Unambiguous assignment of peaks in propyne spectrum is made possible by characteristic vibrational structure of model compounds(ethyne and ethane)and abinitio theory.

Shift of the methyl (CH3) peak in propyne relative to ethane is due to the electronegativity of the ethyne (HCºC) group.

From BL 10.0 (AMO, ALS)Thomas et al, PRL

Ambient pressure photoemission

High resolution C1s Photoelectron Spectra ofhydrocarbons (sharper tool with modern SR)

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(Himpsel et al,1985, NSLS)

Oxidation of Silicon - Dynamics

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What are new opportunities with core level photoemission ?

In-Situ & dynamical studies of chemical reactions at surfaces

What are new opportunities with core level photoemission ?

In-Situ & dynamical studies of chemical reactions at surfaces

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HP-PES Differentially Pumped Optics

Analyzer lens, pumped independently

Experimental cell supplied by gas lines

The Schematic Pictures of Electron Optical System of Ambient Pressure X-ray Photoelectron Spectroscopy (XPS)

X-rays incident at 15° through a 100 nm Al/or SiN window

Sample with Z motion, cold finger and resistive heater

Ogletree, Bluhm, Lebedev, Fadley, Hussain, Salmeron, Rev. Sci. Instrum. 73 (2002) 3872.

BL 9.3.2

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in-situ real-time study of ultra-thin Si gate oxide: Oxidation dynamics

Strong temperature dependence

Si(100) oxidized by water vapour @ .1 torr

Excitation energy 350 eV

Acquisition 1 spectrum / 8 sec

Si+0 BulkSi4+ Si+0 BulkSi4+

Enta, Mun Fadley,Hussain et al. App. Phys. Lett. 92,012110 (2008)

BL 9.3.2

Himpsel PRB 1988

450°C250°C

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Efficient Detection is necessary for study of Dynamics of Chemical Reactions & Radiation Sensitive Samples

•New Scienta 4000 AP-XPS system (A collaborative project between ALS(SSG) and VGScienta):•Optimization using gas dynamics calculations•Tested (April 2008) to perform as expected

Next Generation AP-XPS system

0.2 2 20mbar

First Generation

Next Generation

BL 9.3.2

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Steps Toward Hydrogen Vehicles

Synchrotron research application Synchrotron research application are rapidly growing for are rapidly growing for characterising new materials such as characterising new materials such as carbon nanotubes that may be carbon nanotubes that may be promising material for storing promising material for storing hydrogen safely, efficiently and hydrogen safely, efficiently and compactly. compactly.

The DOE Freedom CAR programDOE Freedom CAR program has set the goal of a material that can hold 6% of the total weight in hydrogen by the year 2010. Theoretical calculations indicate they may exceed these goals substantially.

Nikitin et. al., Phys Rev Lett. 95, 225507 (2005)Funded by DOE, NSF and Global Climate and Energy Project (alliance of scientific researchers and leading companies in the private sector, including ExxonMobil, General Electric and Schlumberger)

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Fuel Cell - Schematic

H2

Anode Cathode

e-

e-

+

+

+

+ +

Proton ExchangeMembrane

LOAD

O2

H2O

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Anode : Hydrogen oxidation Hydrogen gas = Hydrogen Ions + Electrons

2H2 4H+ + 4e-

Cathode : Oxygen reductionOxygen gas + Protons + Electrons = Water

O2 + 4H+ + 4e- 2H2O

Conducting through Membrane External

Circuit

Cathode : the performance of polymer electrolyte membrane fuel cells is limited by the slow rate of O2 reduction (ORR) at Cathode, ~5 orders of magnitude slower than H2 oxidation at Anode

In both cathode and anode, Pt based catalysts are applied to increase the rate of each chemical reactions. Need better material than presently used Pt.

Not too weak!Not too strong!

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The discovery of a unique platinum-nickel alloyrepresents a breakthrough in catalyst research: it is 90 times more active than state-of-the-art platinum catalysts currently used.

Top:In standard Pt catalysts absorption of oxygen on the surface is hindered by the binding of other molecules, such as OH. Bottom: In the new material The nickel atoms change the surface properties such that OH cannot bind as well, leaving room for oxygen.

Research team includes: Argonne and Berkeley National Labs, U. South Carolina.

80% of All Important Chemical Reactions Take Place on Interfaces

Science 315 Jan 2007

BL 9.3.2

O2

OH

Pt

Ni

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AngleAngle--resolved Photoemssion resolved Photoemssion SpectroscopySpectroscopy

InstrumentationData processing

Scientific issues

MaterialsVol. 75, 2003p.473-542

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Band Structure of C60 on Ag (111) and Ag (100) Surfaces – Orientation Dependence

C60 ML / (111) surface C60 ML / (100) surface

-0.20

-0.15

-0.10

-0.05

0.00

0.05

Ener

gy (E

-EF,

eV)

-0.8 -0.6 -0.4 -0.2 0.0 0.2

Γ

k// (1/Å) -0.4 -0.2 0.0 0.2

Γ

k// (1/Å)

Same Hexagon Structure; Completely Different Dispersion!Brouet, Yang, Hussain, Shen et al, Science, 300, 303 (2003); PRL (2004)

(111) surface (100) surface

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-0.2

-0.1

0.0

Bin

ding

ene

rgy

(eV

)

-0.4 -0.2 0.0 0.2

Γ

Γ

Combination of Experiment and Theory(strong orientation dependence)

Dotted Lines: Theory (Louie, Cohen et al) LDA); 2D Images: Experiments

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-0.2

-0.1

0.0

W~135 meVW~100 meV

ΓWang, Brouet, Louie, Hussain, Shen et al

Science 300

C60 (Conclusion)

, 303(2003)

PRL93, (2004)

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Unbiased Biasedno conduction

The Next Leap in Computer Size: the Nanoswitch

Rotenberg et al Science, 313, Aug 2006.

Graphene, a single honeycomb layer of carbon, is the building block of graphite, nanotubes, and buckyballs.

Recent experiments at the synchrotron using angle-resolved photoemission demonstrated that is it possible to use a bilayer of graphene as a switch: current flows when the switch is closed (bilayers electronically close together), and does not flow when the switch is open (bilayers electronically separated).

This proves it is possible to build and control an electronic switch as small as two atoms, paving the way for computers at least 100 times smaller than current technology allows.

Research funded by: DOE, the Max Planck Society, and the European Science Foundation

conduction

Silicon chip

Germaniumtransistor

Carbon Nanoswitch

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Scanning Transmission X-ray Microscope (STXM)

detector

scannedsample

x-rays

zone plate(Au on Si3N4)

OSA

Si3N4Window 50 nm500 x 500 μm

He, air or vacuum

Schematic

0.5 – 9 mm (energy dependent)

OSA – Order Sorting Aperture

Spatial Resolution < 25 nm (ALS BL 11.0)

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Nanoscale chemical imaging ofa working catalyst by STXM

Frank M. F. de Groot (Utrecht University, The Netherlands)Mary K. Gilles, Tolek Tyliszczak (ALS, LBNL)

Nature 456, 222 (2008)

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Improving America’s Billion Dollar Industries: From Paper Coatings to Baby Diapers

DOW Chemical Company funds synchrotron studies on diverse materials in order to characterize new materials and methods for manufacturing. The synchrotron x-ray microscope (STXM) was used to:

…reveal the substructure of hollow latex particles, which helped DOW researchers determine how to make them work as glossing aids in paper coatings

…analyze drug particles that had been enhanced for bioavailabilityto…reveal the phase structure of membranes used purify water.

…characterize super-absorbent polymer materials used in baby diapers

In all these examples, DOW used the experimental results to help develop new process technology for manufacturing plants.

Research funded by DOW Chemical Company

Acrylate

Styrene285.2 eV

288.4 eV

Imaging using different x-ray energies reveals the composition of hollow latex particles (top); and shows the location of drug vs excipient (bottom).

Danazol

1μm

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More Powerful Computers for the Information Age

Improved computational power comes from shrinking transistors to squeeze more of them into a microprocessor. Extreme Ultraviolet (EUV) Lithography is the leading next generation technology to make those continued improvements possible. The pioneering work done with synchrotron radiation has driven this technology forward toward commercialization. Printed image showing

28 nm circuit lines in photoresist

Current technology will allow manufacturers to print circuits as small as 45 nm in width, or 1/2,000th the width of a human hair. EUV lithography technology will extend this down to 22 nm or less, paving the road to 20 GHz computers and beyond.

Funding organizations include SEMATECH, Intel, IBM, AMD, Micron, Samsung, ……..

J. Appl. Phys. 100, 073303 (2006)

(micro exposure tool)

EUV lithography exposure tool using synchrotron radiation

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Sample

X-rays(wavelength λ)

Scattering patternon detector

2θ

Scat

tere

d In

tens

ity (l

og)

Momentum transfer s=4πsinθ/λ

Scattering angle

Pair

Cor

rela

tionρ(

r)

Distance r, (nm)

X-ray scattering gives shape information

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AcknowledgementAcknowledgementAcknowledgement

o Photoemission: Z X Shen (Stanford), Eli Rotenberg, (LBNL, ALS), Xingjiang Zhou (ALS, SSRL, China)

o Inelastic Scattering: Yi-De Chuang, Jinghua Guo; Jonathan Denlinger, (LBNL, ALS), Eric Guillikson, Z. Hasan (Princeton)

o Lensless Imaging: Janos Kirtz, Malcolm Howells(LBNL, ALS)

o Nanoscience characterisation: Franz Himpsel (univ of Wisconsin),Lou Terminello (LLNL), Andreas Scholl (ALS), Jo Stohr (SSRL)

o scattering: Jeff Kortright (LBNL), Mitchel (Dow chemical),Ade (NCU), Howard Padmore

o Coherent Scattering: Steve Kevan and Karine Chesnel (Univ of Oregon, ALS)

o Protein Crystallography: Corie Ralston, Paul Adam, Gerry McDermott, James Holton (LBNL)…

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Conclusions

Thank You for your attention

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