Transferring CVD Graphene from Copper
SOURCE: Melina Blees (McEuen Group)
ADDED: 2/17/13
Flatten copper using clean microscope slides. In the e-beam resist room, spin 495 PMMA A8 at 40000rpm for 60s, open bowl. Bake at 90C for ~a minute; this isn't really required. Etch by soaking in copper etchant for about an hour (all copper will be visibly gone). Scoop to three consecutive DI water baths using a piece of blank silicon, then onto your receiving substrate. Let it dry, then remove the PMMA with a 3-hour acetone soak and IPA rinse.
SOURCE: McEuen Group
ADDED: 2/27/13
Spun PVA nanotube transfer:
Cover NTs with 100nm of gold. Spin a layer of PVA (I use Emulsitone Laser Scribing Solution 1146, which is PVA in water and can be stored at room temperature) at 3000 RPM, 1000 RMP ramp, for 30s. Bake the chips for 30 minutes in a 70 C oven. Using tweezers, peel the NT/Au/PVA PVA film off of the donor substrate and place it on the receiving substrate. Use a gloved finger to smooth the film down and eliminate any bubbles. If you don't get decent adhesion to the surface - i.e. if the film would rather curl up or peel off than stick to the receiving substrate - then your PVA layer is probably too thick. Carefully place the chip in a warm DI water bath for one hour. Do not flow water over the chip or otherwise disturb it, as that can cause the film to release from the surface. Let the chip air-dry. You will notice that the NT/Au film will be mostly free of PVA, and will look as though it was evaporated onto your new surface rather than just being placed on top. Run the dry chip through an oxygen clean for 10-30 minutes (150 mtorr, 20 sccm, 150W). Place the clean chip in gold etchant (TFA) for two minutes. Rinse with water.
