I had tried to generate nano-pillars using AAO template, but I couldn't grow nano-pillars with perfect order. Rather, slanted nano-pillars were only formed. So please help me about the placement of AAO above a thin film.
I agree with Wouter, however additionally after Au sputtering You have to electrodeposit Au at the pore bottoms. Finally, then You can do further electrochemical deposition.
There's also an alernative way reported for the first by Furneux et al. and developed i.e. by J. Montero-Moreno (check their papers if You're interested): a barrier layer thinning (BLT). After the second step of anodization You're exponentially decreasing the voltage to about 1 V and have barrier layer thinned what will allow You to do electrodeposition. The advantage? Your membrane is on Al substrate, so it's not so brittle and You have less steps to make :-) I wish You luck with Your research! If You have any questions don't hestitate to send me a message.
Dear Shamjid, the best option is to sputter the metallic contact directiy on top of the AAO instead of placing the AAO on top of a thin film. I am currently working on a video for the Journal of Visualized Experiments in which this will be explained very well, so I hope that this video will be finished soon since I think that that video will help you a lot to make things more clear :)
I agree with Wouter, however additionally after Au sputtering You have to electrodeposit Au at the pore bottoms. Finally, then You can do further electrochemical deposition.
There's also an alernative way reported for the first by Furneux et al. and developed i.e. by J. Montero-Moreno (check their papers if You're interested): a barrier layer thinning (BLT). After the second step of anodization You're exponentially decreasing the voltage to about 1 V and have barrier layer thinned what will allow You to do electrodeposition. The advantage? Your membrane is on Al substrate, so it's not so brittle and You have less steps to make :-) I wish You luck with Your research! If You have any questions don't hestitate to send me a message.
We also previously used the BLT method (good point!) In this recent paper you can find the procedure we've used to make our "dendritic" template pores: http://pubs.rsc.org/en/content/articlelanding/2014/ta/c3ta14551d#!divAbstract
Furthermore I never did the mentioned Au electrodeposition at the pore bottoms, but instead we always carefully isolate the back side of the membrane with a glass slide, which also can be used for mechanical support (again I wish the video was there yet ;))
Additional Au deposition provides better filling factor, so almost 100% of pores are filled. Otherwise, without Au deposition less pores can be filled with desired metal. You can find useful details in papers published by Zaraska et al. about NWs:
even few square cm of NWs arrays are formed with this approach. However, I prefer BLT, because electrodeposition of Au from i.e. K[Au(CN)2] baths is expensive.
If I coat material(metal or semiconductor) onto the AAO template, how can I grow the nano-wires. Rather I place AAO on the coated thin film, I can grow nano-wire by heating the material up to the melting point. When it reaches that temperature, the thin film material will melt and rise into the AAO pores. But even though I couldn't form the perfect standing wires, instead it formed as slanted wires.