I would use an AFM - tapping mode will get you some topography - a
conductive probe will give you a better idea of the actual grain
boundaries. Use very sharp tips, tho (10nm radius of curvature or less),
and be prepared for them not to last very long (2 to 5 scan passes). We
have made long lasting conductive probes, but generally for our own use
only.

--
Tom Rust
Nanochip Inc
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Oakland, CA 94621
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