What is Scanning & Transmission Electron Microscopy?
- Major installations are standard equipment
in large corporations and universities, costing ~ $1 million.
- TEM is principally a research instrument with Angstrom
level resolution in best cases (similar to AFMs).
- Sample preparation is a significant problem. Nonconductive
samples require a conductive coating (gold or carbon sputtered).
- SEM/EDAX is more versatile and can be used for
- SEM Main Advantage: Combination of excellent topographical
information at 5,000 to 20,000x for most industrial uses,
coupled with elemental analysis of features. Research instruments
go to 500,000x and higher.
- SEM Main Disadvantages: Cost and sample preparation time.
mounted on cantilever arm 100 to 200 microns long. Tip radii
are in the nano meter range.
- Exception to expensive SEM installations:
"The Personal SEM" by RJ Lee Instruments, Ltd, Trafford, PA
Cost range - $65,000 to $85,000, depending on options selected.
- Can analyze individual particles from components.
Note: composition data are semi-quantitative without standards,
and lower limits to elements detected, usually around sodium,
without the more expensive unit and Light Element attachment.