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Nov 11 2009

AVS Conference notes (unedited): Day 2

8:40am My talk. Nobody came.

9:00am Fe3O4 termination. STM below the Velway temperature. This is another talk about residual water vapor effects on samples in a UHV chamber. Is this very interesting? Clean the damn sample. Regular termination is tetrahedral Fe, metal insulator transition. People filed at the end of my talk to see THIS?

9:20am STM of VO2, metal insulator transition. Promising gas sensor. Right. Surface MIT can happen for V2O5. They desorb the carbon at 100C??? How?! 2D band gap maps, turns into something partly metallic at 80C. No correlation with copography.

9:40am Adsorption of alcohol on alpha-Al2O3. Ultra high field NMR. Al tetrahedral and Al octahedral seen on NMR, and some other signal (maybe penta). Al+3 which is just at the surface. This is like the damn surface science meeting. I'm snoozing. Diebold: "Very nice." Whatever.

2:00pm E-beam induced deposition (EBID) and purification of gold. This is so cool! You put down a precursor like CVD and use a focused electron beam to dissociate the molecule and leave gold behind. They made a map of the earth 400nm wide in gold. This guy uses O and H to clean it up, since the precursor leaves behind contaminants when it's dissociated. Atomic H and O work pretty good. All of this is at room temp. Good for 'rapid' prototyping; takes 30 hrs for a cleaned structure.

2:20pm Cryogenic EBID. Low-T improves sticking probability. Dose with e-gun off, then pattern. Uses an SEMFIB, cools to 120K. Morphology changes w/ time somewhat. Can be used for photomask repair. He made some cool pictures and structures similar to dual damacene stuff.

2:40pm Low-energy e-beam on graphene. Thickness with auger. Auger electron diffraction. Lots of stuff here. ESD broad beam study of graphene (1st time). Lots of H+ on it for some reason, probably at step edges. ESD shows many organic fragments. Desorption threshold at 20eV. Knotek Fiebelmann mechanism. (New J. Phys 10 (2008) 093026. Graphene oxide? Hammer's method. Forms graphene oxide by low energy electron irradiation.

4:00pm Nucleation of EBIDs. 4.5nm dots possible, even as low as 0.7nm dot pattern. Needs 300keV e-beam. Leaves behind 1.6nm of amorphous carbon. I have no idea what he's talking about. Where's the nucleation?

4:20pm People keep trying to dim the lights. They are fluorescents, they don't dim. Christ. Direct local deposition w/ EBID & ALD. Oh. You just make a seed layer with EBID and then use ALD to grow more (with high purity). Seed layer of 0.5nm is enough. Limited to low aspect ratios because of ALD non-directionality.

4:40pm People are piling in. This one must be highly anticipated. Trying to break a specific bond with low-energy electrons. Dissociative electron attachment. This is boring chemistry. Eventually needed a buffer layer on thiols at low temp to break only the methyl terminations. This talk could have been 20 mins, was 40.