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Scanning Probe MicroscopesSPM History of scanning probe microscopes SPM System Overview Piezoelectric Effect Scanning Tunneling Microscope (STM) Atomic Force Microscope (AFM) Force vs. Distance Curve Scanning modes Vendors http://mechmat.caltech.edu/~kaushik/park/contents.htm

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History of Scanning Probe Microscopes Phonograph record

http://www.nanoworld.org/english/museum.html

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History of Scanning Probe Microscopes

1929 Gustev Schmalz Stylus profiler

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History of Scanning Probe Microscopes 1971 Russel Young Topographiner A non-contact

stylus profiler

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History of Scanning Probe Microscopes 1981 Gerd Binnig & Heinrich Rohrer Scanning Tunneling Microscope (STM)

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History of Scanning Probe Microscopes Atomic Force Microscope (AFM/SFM) Gerd Binnig, Calvin Quate & Christoph

Gerber 1986

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SPM System Overview

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SPM Scan HeadSTM

AFM

Non Contact AFM

Contact AFM Lateral Force

Microscopy

Force Modulation

Laser should be switched on to operate

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SPM Scan Head

First:Adjust cantilever alignment so laser is aligned on the cantilever

Second:Adjust detector alignment until red lights are out and green light is on.

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Pre-Mounted AFM Probe Tip

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Cartridges

AFM Cartridge STM Cartridge

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Digital Voltmeters

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A+B Should be Maximized

A-B Should be Minimized

A = 1+3 B = 2+4

1 2

3 4

Top = 1+2

Bottom = 3+4

LFM records Top-Bottom and should be minimized

Photodetector

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Scanning Tunneling Microscope

Applications System Components Tube scanner Piezoelectric effect Theory of operation Operating modes Advantages & Disadvantages

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Applications

High resolution images at atomic resolution. Ability to manipulate individual atoms. http://www.almaden.ibm.com/vis/stm/gallery.html

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STM System Components

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Piezoelectric tube scannerPiezoelectric materials are used to create a tube scanner. This forms one of the basic components of scanning probe microscopes.

These can be used to manipulate an object in three dimensions under electronic control.

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Piezoelectric EffectCertain materials exhibit what is called the piezoelectric effect. (Demo)

This is an effect where changing the size of an object results in a voltage being generated by the object.

Conversely when a voltage is applied to a piezoelectric object then the size of the object changes.

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Piezoelectric Effect

Piezoelectric materials have an asymmetric unit cell like a dipole.

If these crystals are grown in the presence of a strong electric field then the crystal grains will align and the piezoelectric effect is created.

PZT: Lead zirconium titanate is one of the most common piezoelectric materials.

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Unit Cell with Dipole

CubicT > Tc

TetragonalT < Tc

The central atom is displaced resulting in a unit cell with a dipole moment.

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Piezoelectric EffectCrystal grains structure

Grown in an electric fieldUnit cell dipoles align

Not grown in an electric fieldRandom orientation

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STM Theory of operation

Tunneling Current

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Scanning Tunneling Microscope

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Operating modes

Constant height modeCurrent changes exponentiallyRequires a smooth surface

Constant current modeBeware of insulators

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STM Advantages & Disadvantages Advantages

Able to obtain very high resolution images of conductors and semiconductors.

Probe tips can be made out of wire. Inexpensive to purchase ~ $10,000

Disadvantages Will not work with insulators. If there are insulating materials present on the sample

you can crash the tip. Often need to be used under vacuum.

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Scanning Tunneling Microscope

Applications System Components Tube scanner Piezoelectric effect Theory of operation Operating modes Advantages & Disadvantages

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Atomic Force Microscope

System Components Force vs. Distance Performance & Images Scanning Modes & Probe Tips Vendors

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AFM System Components

Demo

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Force vs. Distance

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Performance

The piezoelectric tubes have a movement resolution of 1 nm/volt.

Magnifications of 5,000,000x can be achieved. Resolution of 10 pm Can operate in air and under liquids Atomic force microscopes can be used on many different

surfaces. AFM is a versatile and easy to use tool. Images http://www.nanoscience.com/ AFM Activity WS 13

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Scanning Modes and Probe Tips Standard probe tips High resolution probe tips Magnetic force microscopy Frictional force microscopy/Lateral force microscopy Elasticity/hardness measurements/Force modulation microscopy Scanning Capacitance Thermal scanning microscopy – two different metals/ thermo couple Near-field Scanning Optical Microscopy/Light funnel Piezoelectric cantilever Electrostatic force microscopy Dip pen nanolithography Surface oxidation Many different companies make probe tips for scanning microscopes.

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Scanning Probe Microscope Vendors Veeco http://www.veeco.com/ JEOL http://www.jeol.com/ Nanoscience Instruments

http://www.nanoscience.com/ Asylum Research http://www.asylumresearch.com/ JPK Instruments http://www.jpk.com/index2.htm Molecular Imaging http://www.molec.com/ Nanofactory Instruments

http://www.nanofactory.com/ Nanotec Electronica http://www.nanotec.es/ NT-MDT http://www.ntmdt.ru/ Quesant http://www.quesant.com/ WITec http://www.witec.de/ Pacific Nanotechnology

http://www.pacificnanotech.com/ Nanoics Imaging http://www.nanonics.co.il/main/ Schaefer-TEC http://www.schaefer-tec.com/ Windsor Scientific http://www.windsor-ltd.co.uk/

LOT Oriel Ltd http://www.lot-oriel.com/uk/htm/all/home01.php

Atomic Force http://www.atomicforce.de/ Mikro Masch http://www.spmtips.com/ Surface Imaging Systems http://www.sis-gmbh.com

/ Physik Instrumente http://www.polytecpi.com/ Accurion http://www.accurion.com/ Advanced Surface Microscopy

http://www.asmicro.com/ Hysitron http://www.hysitron.com/ Infinitesima http://www.infinitesima.com/ Nanograph Systems

http://www.nanographsystems.co.uk/ Nanonis

http://www.nanonis.com/nanonis/avs/home/index.html

PSIA http://www.advancedspm.com/ Triple-O Microscopy http://www.triple-o.de/ Bioforce http://www.bioforcelab.com/

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Scanning Probe Microscopes

System Components Force vs. Distance Performance & Images Scanning Modes & Probe Tips Vendors

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Links

http://stm2.nrl.navy.mil/how-afm/how-afm.html http://www.ikm.uni-karlsruhe.de/forschung/pzt_webseiten/eng/

basics/ferro_main_eng.html http://cst-www.nrl.navy.mil/lattice/struk/pzt_t.html http://www.chembio.uoguelph.ca/educmat/chm729/STMpage/

stmconc.htm http://www.2spi.com/catalog.html