Think about the surface preparation of the chip. Organic residues can be a pain. Oxygen plasma is the industry standard for removing all residues.

We had trouble getting alumina to stick to brand new silicon oxide wafers. Fresh silicon oxide is so hydrophillic that the alumina has no reason to deposit (it just stays dissolved in the water). Ironically, the sticking procses is aided by photoresist residue, or the residue deposited by a gelpak.

• Sonicate iron nitrate based catalysts 30-60 min (Ferritin should not be sonicated)
• Stir until ready to use
• Add catalyst to chips in large mound, wait 2-10 minutes, rinse with DI water

If you are using a photoresist mask, you will now have to remove the photoresist (5 minute soak in acetone)

• Rinse with acetone and then IPA, dry with N2
• Check with optical microscope in Janet Tate's lab.
• Growth may be better if you do it within 3 hours of depositing the catalyst