tools of the nanosciences there’s plenty of room at the bottom it is my intention to offer a prize...

Tools of the Nanosciences• There’s plenty of room at the bottom• It is my intention to offer a prize of $1,000 to

the first guy who can take the information on the page of a book and put it on an area 1/25,000 smaller in linear scale in such manner that it can be read by an electron microscope.

• another $1,000 to the first guy who makes an operating electric motor---a rotating electric motor which can be controlled from the outside and, not counting the lead-in wires, is only 1/64 inch cube.

-Richard Feynman, 1960

Tools for Measuring Nanostuctures

• Scanning Probe Instruments– Atomic Force Microscope (AFM)– Scanning Tunneling Microscope (STM)– Magnetic Force Microscope (MFM)

• Spectroscopy

• Electrochemistry

• Electron Microscopy

Atomic Force Microscopy

• Probe is nanoscale dimensions, often only a single atom in size

• Electronics are used to measure the force exerted on the probe tip as it moves along the surface

Picture of MoO3 single crystal by an inter-atomic-force microscopy

Scanning Tunneling Microscope

• The amount of electrical current flowing between a scanning tip and a surface is measured.

• Can be used either to test the local geometry or to measure the local electrical conducting characteristics

Silicon atoms as viewed with the scanning tunneling electron microscope (STEM).

Spectroscopy

• Nuclear Magnetic Resonance Imaging– is a physical phenomenon based upon the

quantum mechanical magnetic properties of an atom's nucleus.

Magnetic Force Microscopy

• The tip the scans the surface is magnetic.

• Used to sense the local magnetic structure on the surface.

• Works in a similar way to the reading head on a hard disk drive or audio cassette player

• .

10x10 µm MFM images of magnetic tape, topography (A) and phase image (B). The magnetic domains are ~ 650 nm in length.

Electrochemistry

• Deals with how chemical processes can be changed by the application of electric currents, and how electric currents can be generated from chemical reactions.

• Nature of the surface atoms in an array can be measured directly

Electron Microscopy• Electrons are accelerated and passed through a sample. As the electrons

encounter nuclei and other electrons, they scatter. By collecting electrons that are NOT scattered, we can construct an image that describes where the particles were that scattered the electrons that didn’t make it through.

• Based on the use of electrons rather than light to examine the structure and behavior of the material.