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1) Decreasing contact resistance:
- Right e-beam dose to minimize residue after development.
-Development times. Test: AFM before spinning and after development. - Pumping before evaporation: Heating? How long? Outgassing issues?
- Is UV ozone before evaporation good? Does it damage graphene? What
parameters (direct UV exposure, dark exposure, time, etc)? - What metals work best? Under what conditions?
2) Suspending graphene and gates:
- CPD or not?
- Electrode thickness and metals?
- How to prevent rippling (best geometry)?
3) Graphene quality:
- Are different sources of graphite equally good?
- Substrate cleaning recipes
- Deposition strategies
- Current and/or heat annealing? Recipes and parameters.
- CVD versus exfoliated graphene
4) Etching and nanoribbon formation O2 or Ar plasma? PMMA, HSQ, and other masks
Catalytic methods (Ni and other nanoparticles, etc)
5) Dielectrics (substrates, ALD, e-beam deposited, etc)
How to improve SiO2?
- How to get ALD to work reliably (NO2 functionalization? thin oxide seed?)?
- Does high-K really improve mobility?
6) Lift-off issues and after-lift-off cleaning
- Best lift-off recipes, best solvent? (warm/cold acetone, other
resist strippers?) - After lift-off cleaning: annealing in forming gas, what temperature,
how long? What happens to contacts?
Looking forward to seeing you this Friday.
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