What has enabled Nanoscience?

• Advances in Computing Power

• New Generation of Scientific Instruments

Scanning Probe Microscopes

An incomplete list . . . .

Very Sharp Tip scans over sample surface

Scanning Tunneling Mic. (STM)

Atomic Force Mic. (AFM)

Magnetic Force Mic. (MFM)

Near Field Scanning Optical Mic. (NSOM)

ATOMIC RESOLUTION

Why Nano now?

Scanning Probe Microscopy

• SCANNING TUNNELING MICROSCOPE (STM) First SPM: 1983. The Since then, many types of SPM:

• ATOMIC FORCE MICROSCOPY (AFM, also known as scanning force microscopy)

•MAGNETIC FORCE MICRSCOPY (MFM)

• near field scanning optical microscopy (NSOM)

• Others ….

Scanning Probe Mic: Sharp tip

Scanning Probe Tip

SampleSample

Sharp tip moves over surface and measures some property

STM, Nobel Prize 1986

Binnig and Rohrer

STM, Imaging

SampleSample

- Battery +

Current

Tunneling Current

STM images, Examples

http://cwx.prenhall.com/bookbind/pubbooks/hillchem3/medialib/media_portfolio/07.html

STM Images, Eigler 1

Eigler et al. NATURE 363, 1993

Don Eigler, IBM

STM Images, Eigler 2

Don Eigler, IBM

STM Images, Wilson Ho 1

Wilson Ho, UC Irvine

STM Images, Wilson Ho 2

Wilson Ho, UC Irvine

Handmaking Molecules!: Wilson Ho 3

Wilson Ho UC, Irvine.

Atomic Force Microscopy

Microscope Microscope TipTipMicroscope Microscope TipTip

Sample Surface scanned back and forthSample Surface scanned back and forthSample Surface scanned back and forthSample Surface scanned back and forth

MirrorMirrorMirrorMirror

LASERLASERLASERLASERLASER DetectorLASER Detector

ComputerComputer ComputerComputer

DisplayDisplayDisplayDisplay

• A Thermo Microscopes Explorer AFM

AFM tips

Made from Si or Si3N4

Carbon nanotubes

This montage of atomic force microscope images above shows the (0001) growth surface of a 6H-SiC crystal grown by physical vapor transport. The single steps on the surface are each 15.2 Angstroms high, the lattice parameter along [0001]. Carnegie Mellon University Material Science and Engineering

Pittsburgh, PA, USA

http://neon.mems.cmu.edu/rohrer/rohrer.html

AFM images: Materials

AFM images:Biological Samples

The image shows human eurythrocytes, or red blood cells, imaged in a buffer solution. The shape of the cell is important to its function. Atomic force microscopy can be used to identify the unique characteristics of the cell shape and size.

Luana SchefferTel-Aviv University

School of Medicine/Department of Physiology

Tel-Aviv, Israel

Images and Manipulation of DNA !

Departmento Física de la Materia Condensada UAM

Asylum Research

Pulling on Biological Fibers

More than topography

Simultaneous C-AFM images of carbon fiber-epoxy composite used in aircraft manufacturing, acquired simultaneously in topography (left), force modulation (center), and phase detection (right), modes. The force modulation image (center) shows the harder (brighter) carbon fiber in the darker colored epoxy matrix. The phase image (right), shows similar image contrast, and shows differences in the visco-elasticity or "stickiness" across the fiber. Field of view 15 µm.

Topography Hardness Visco-elasticity

AFM images: Carbon Nanotubes

AFM images: Adenovirus

Viral DNA

Atsuko Negishi UNC Materials Science

AFM, (sub)atomic resolution

Titin unfolding

Titin

http://www.ks.uiuc.edu/Research/smd_imd/titin/

Pulling Titin 2

Pulling Titin 3

AFM feedback

LASER DETECTORLASER

COMPUTER

SAMPLE

SCANNER

VIDEO

AFM HEAD

TIP

CONTROL

CANTILEVER

Contact Mode

Deflection ~ Force

Piezoelectric translators

DC deflection maintained by feedback loop

Non-Contact and Tapping Mode

Amplitude ~ Force

Piezoelectric translators

Amplitude maintained by feedback loop

Interaction Potential

Energy

Tapping Mode

Contact mode

Non-contact Tip Sample separation

Resolution and Artifacts

5-20nm5-20nm

Tip Shape Effects

5-20nm

LEGO Atomic Force Microscope