Microsystems LaboratoryUC-Berkeley, ME Dept.

1Liwei Lin, University of California at Berkeley

Introduction to Nanotechnology and Nanoscience – Class#2

Liwei Lin

Professor, Dept. of Mechanical Engineering Co-Director, Berkeley Sensor and Actuator CenterThe University of California, Berkeley, CA94720

e-mail: lwlin@me.berkeley.eduhttp://www.me.berkeley.edu/~lwlin

Microsystems LaboratoryUC-Berkeley, ME Dept.

2Liwei Lin, University of California at Berkeley

Course Homepage - 3

Microsystems LaboratoryUC-Berkeley, ME Dept.

3Liwei Lin, University of California at Berkeley

Outline

� Nanoscale Properties� Nanofabrication: Top-down Technologies

& Bottom-up Processes� (some materials from Professor Lydia Sohn)

Microsystems LaboratoryUC-Berkeley, ME Dept.

4Liwei Lin, University of California at Berkeley

Microsystems LaboratoryUC-Berkeley, ME Dept.

5Liwei Lin, University of California at Berkeley

DNA Detection

Microsystems LaboratoryUC-Berkeley, ME Dept.

6Liwei Lin, University of California at Berkeley

DNA Detection

Microsystems LaboratoryUC-Berkeley, ME Dept.

7Liwei Lin, University of California at Berkeley

Molecular ElectronicsThe Future?

Microsystems LaboratoryUC-Berkeley, ME Dept.

8Liwei Lin, University of California at Berkeley

National Nanotechnology Initiative

Even though nanoscience & nanotechnology had existed for many years, it was Present Bill Clinton in January 2000 who catapulted (for better or for worse) the field into mainstream science & engineering and society—Proposed the NNI which has now become a multibillion dollar investment in the US—see http://www.nano.gov for history and current info. on the NNI

• Estimated world-wide investment on nanotechnology and nanoscience is $8.6B in 2004

Microsystems LaboratoryUC-Berkeley, ME Dept.

9Liwei Lin, University of California at Berkeley

Nanotechnology Explosion

Microsystems LaboratoryUC-Berkeley, ME Dept.

10Liwei Lin, University of California at Berkeley

Some big numbers

Federal 2002 nanofunding $622 millionEstimated nanosales volume in 2015 $1.2 trillionStates with active nanodevelopments 24

Microsystems LaboratoryUC-Berkeley, ME Dept.

Why should I take this course?

11Liwei Lin, University of California at Berkeley

Microsystems LaboratoryUC-Berkeley, ME Dept.

Who is in this class (2015)?

12Liwei Lin, University of California at Berkeley

25

7

2

2

2

1

1

1

1

0 5 10 15 20 25 30

Mechanical Engineering

Materials Science

Chemical Engineering

Chemistry

Bioengineering

Engineering Physics

Chemical Biology

Molecular/Cell Biology

Civil Engineering

Microsystems LaboratoryUC-Berkeley, ME Dept.

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4

29

5

2

0 5 10 15 20 25 30 35

Graduate

Senior

Junior

Sophomore

Who is in this class (2015)?

Microsystems LaboratoryUC-Berkeley, ME Dept.

“Nanoscience & ME”

What does a mechanical engineer do in nanoscience?

Materials scientist?Chemical engineer?

Chemist, bioengineer, biologist, physicist, civil engineer?

14Liwei Lin, University of California at Berkeley

Microsystems LaboratoryUC-Berkeley, ME Dept.

Research� Nanoscience is hot!� National labs, academia, industrial research

organizations (IBM, PARC)

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http://www.mrs.org/science-as-art/

“Nano-Explosions”Color-enhanced scanning electron micrograph of an overflowed electrodeposited magnetic nanowire array (CoFeB), where the template has been subsequently completely etched. It’s a reminder that nanoscale research can have unpredicted consequences at a high level.

- Fanny Beron, École Polytechnique de Montréal, Montréal, Canada

Microsystems LaboratoryUC-Berkeley, ME Dept.

16Liwei Lin, University of California at Berkeley

MEL. LinL. SohnX. ZhangC. Grigoropoulos

MSEJ. WuO. DubonR. Ramesh

ChemER. MaboudianA. KatzS. Muller

ChemistryP. YangP. AlivisatosG. Somorjai

Civil EngineeringS. GovindjeeW. NazaroffC. Ostertag

BioengineeringD. LiepmannK. HealyL. Lee

PhysicsA. ZettlM. CrommieF. Hellman

Berkeley Nanotechnology & Nanoscience Institute (BNNI)Marvell Nanofabrication Laboratory, SDHBerkeley Sensor & Actuator Center (Cory Hall)Berkeley Nanotechnology Club https://www.ocf.berkeley.edu/~atwu/

Microsystems LaboratoryUC-Berkeley, ME Dept.

17Liwei Lin, University of California at Berkeley

NanoScience in Mechanical Engineering

Energy – energy storage, renewable energySensing – gas sensors, chemical sensors, etc.Optics

Cu2O nanowires for photo-electrochemical water splitting (Lin Lab)

“Superlens”(Zhang Lab)

Microsystems LaboratoryUC-Berkeley, ME Dept.

18Liwei Lin, University of California at Berkeley

NanoScience in Materials Science

� Nanomaterial synthesis, material properties, and characterization

In-situ TEM nanomechanics (Andrew Minor Lab)

Strain engineering of VO2nanobeams (Junqiao Wu Lab)

Microsystems LaboratoryUC-Berkeley, ME Dept.

19Liwei Lin, University of California at Berkeley

NanoScience in Bioengineering

� Virus-based piezoelectric energy generation� Super-resolution imaging� Drug delivery

Seung-Wuk Lee Lab:

M13 bacteriophage piezoelectric generator6 nA, 400 mVOperates a liquid crystal display

Microsystems LaboratoryUC-Berkeley, ME Dept.

20Liwei Lin, University of California at Berkeley

NanoScience in Physics & Chemistry

� Physics• Nanomechanics• quantum computation• quantum teleportation• artificial atoms

� Chemistry• carbon nanotubes• Nanowires• self-assembly• structures based on DNA• supermolecular chemistry

Lateral Quantum Dot Leo Kouwenhoven

Superconducting QuBitJohn Clarke

Carbon Nanotube Cees Dekker

Tetrapod Paul Alivisatos

Microsystems LaboratoryUC-Berkeley, ME Dept.

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NanoScience in Civil Engineering

Materials – nano-reinforced materialsEnvironmental chemistry Water treatment

Nanomaterials for water purification:Journal of Nanoparticle Research (2005)7: 331–342

Microsystems LaboratoryUC-Berkeley, ME Dept.Nanotech in the Bay Area

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Nanomix - hydrogen storage

Neophotonics – photonic integrated circuitsNanogram Devices-nanomaterials synthesis

Sila Nanotechnology – Li-ion batteries

Alphabet Energy– Thermoelectrics Quantum Dot Corp. – Nanocrystals for biomolecular detection

HP – quantum science researchAgilent-chemical/medical diagnostic equipmentNanosolar – low cost PV

Crossbar Inc – non-volatile memory

Nanostellar– emission control & energy efficiency

http://www.nanotech-now.com/business-by-location.htm

Optiva– LEDs

IBM – Li-air batteries

Lumiphore–biological detection

Microsystems LaboratoryUC-Berkeley, ME Dept.

23Liwei Lin, University of California at Berkeley

Take ME118ME 218N!

“Nano PacMan”

Scanning electron microscope image of a copper oxide cluster, 3.5 microns in diameter, prepared by evaporation and condensation over an alumina substrate. The smiley nose and eye are present in the original SEM image, which has only been color-enhanced. - Elisabetta Comini, University of Brescia, Italy

http://www.mrs.org/s10-science-as-art-winners/

Microsystems LaboratoryUC-Berkeley, ME Dept.

24Liwei Lin, University of California at Berkeley

Why Nanostructures?

IC & MEMS > 100 nm• Batch manufacturing – low cost• Multi-domain Integration (Electrical, mechanical,

fluidic, optical …) Nanotechnology < 100 nm

• Quantum effects in nanostructures (quantum dots, wires, tubes …)

• High surface area to volume ratio – high sensitivity

Microsystems LaboratoryUC-Berkeley, ME Dept.

25Liwei Lin, University of California at Berkeley

Size-Dependent Properties

At the nanometer scale, properties become size dependent!

For example,

•Thermal properties •Mechanical properties•Optical properties•Electrical properties •Magnetic properties

New properties enable new applications

Microsystems LaboratoryUC-Berkeley, ME Dept.Surface Area to Volume Ratio

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(a) (b)

(c) (d)

Tomato seed

Au nanoparticle

Cell

http://web2.clarkson.edu/programs/goia_group/res_materials_modif_au.php

Microsystems LaboratoryUC-Berkeley, ME Dept.

Chemical reactivity

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vs

Au nanoparticle

InertCatalyst

Microsystems LaboratoryUC-Berkeley, ME Dept.

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Mechanical Properties� At the nanoscale, surface and interface forces become dominant.� For example,

Adhesion forcesCapillary forcesStrain forces

Surface coatings are extremely important to prevent stickingin nanoscale electro-mechanical systems (NEMS)

Microsystems LaboratoryUC-Berkeley, ME Dept.

29Liwei Lin, University of California at Berkeley

Stiction in Micro/Nano Structures

� Strong capillary forces during the releasing process and pin down the free-standing microstructure

Anchor Micro Beam Structure

Silicon Substrate

Stiction AreaLiquid

Microsystems LaboratoryUC-Berkeley, ME Dept.

30Liwei Lin, University of California at Berkeley

Microstructure Stiction Examples� Shorter beams may survive stiction problems*

*Carlos Mastrangelo, Univ. of Michigan

Mastrangelo et al., “Mechanical Stability and Adhesion of MicrostructuresUnder Capillary Forces,” IEEE/ASME J. of Microelectromechanical Systems,Vol. 2, 44-55, 1993

Microsystems LaboratoryUC-Berkeley, ME Dept.

31Liwei Lin, University of California at Berkeley

Anti-Stiction Coating

� Self-assembled monolayer (SAM) coating by using OTS (octadecyltrichlorosilane) - C18H37SiCl3

hydrophilic0 - 30o

Silicon Substrate

concave

~ 114o

hydrophobicSilicon Substrate

convex

Microsystems LaboratoryUC-Berkeley, ME Dept.

32Liwei Lin, University of California at Berkeley

Melting Temperature

Nanocrystal size decreases

Surface energy increases

Melting point decreases

3 nm CdSe nanocrystal melts at 700 K compared to Bulk CdSe at 1678K

Microsystems LaboratoryUC-Berkeley, ME Dept.

Quantum Mechanics

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vs

5 g/cm3

E ≈ kT

Quantum dot

Microsystems LaboratoryUC-Berkeley, ME Dept.

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Rayleigh Light-Scatteringof Nanocrystals

Shape, Size, and Composition Matter

Microsystems LaboratoryUC-Berkeley, ME Dept.

35Liwei Lin, University of California at Berkeley

Optical Absorption

Microsystems LaboratoryUC-Berkeley, ME Dept.

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Effects of Confinement of Charge Carriers

E

D(E)

3-D 2-D

1-D

ZnO

dCdSe 4.63.63.12.42.1

d (nm)

ddCdSe 4.63.63.12.42.1

d (nm)

(Paul Alivisatos, UCB)

Example: CdSe quantum dotsFluoresces vs. wavelength

(After Arum Majumdar, UCB)

0-D

CdSe

Microsystems LaboratoryUC-Berkeley, ME Dept.

What’s going on here?

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Gold nanoparticles CdSe quantum dots

vs.

Microsystems LaboratoryUC-Berkeley, ME Dept.

Aspect Ratio

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vs

Microsystems LaboratoryUC-Berkeley, ME Dept.

39Liwei Lin, University of California at Berkeley

Electrical Properties: Tunneling Current

� At the nanometer scale, electrical insulators begin to fail to block current flow

� Quantum mechanical effect known as tunneling� Tunneling current increases exponentially as the

thickness of the insulator is decreased� Tunneling is the basis of the scanning tunneling

microscope and covalent chemical bonding

Microsystems LaboratoryUC-Berkeley, ME Dept.

Strength-to-weight ratio

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45 GPa

http://www.owlnet.rice.edu/~biy/Selected%20papers/01TAPhys.pdfhttp://cnx.org/contents/f3abd155-e65d-4155-bd2c-9b435b6d2f6a@4/Carbon_Nanomaterials

vs.

520 MPa8 g/cm3

Pa/(kg/m3)1 g/cm3

Microsystems LaboratoryUC-Berkeley, ME Dept.

41Liwei Lin, University of California at Berkeley

Nanotube Composite

Microsystems LaboratoryUC-Berkeley, ME Dept.

42Liwei Lin, University of California at Berkeley

Size-Dependent Properties

At the nanometer scale, properties become size dependent!

For example,

•Thermal properties — melting temperature•Mechanical properties — adhesion, capillary forces•Optical properties — absorption and scattering of light•Electrical properties — tunneling current•Magnetic properties — superparamagnetic effect

New properties enable new applications