The Nanoscale World

Conductive AFM

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Yuji SUZUKI posted on Wed, Jul 14 2010 6:52 AM

dear Forum speakers

 

I am currently working on the conductive AFM using diimension 3100.

I have been trying to do some IV measurements on a zinc oxide nanowire but unsuccessful as the IV  I get on the same spot, with the same parameters are different

questions:

 

- what is the best tip to use? (currently using PPP-EFM)

- what is the best applying force?

- has anyone published an IV measurement using cAFM on nanowire?

- any good tips?

 

 

thank you very much for your time,

 

 

Yuji

 

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Answered (Not Verified) replied on Wed, Jul 14 2010 5:31 PM

Hi Suzuki-san,

The choice of the tip greatly depends on your sample. The problem in conductive AFM is often the ability to make "good" contact between the sample and probe-tip and at the same tip preserve the conductive coating of the tip. Hence the significant variability on some samples with applied force. I have had good success with DDESP-type cantilevers (DDEPS, DDESP-FM). The diamond coating is quite robust when compared to the typically used metal coating. These tip are, however, often not as sharp so you are trading in a bit of lateral resolution when compared to the metal coated ones. Forces during I/V curves have to be high enough to allow a reliable electrical conection and for imaging low enough to not effect the sample (too much).

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Points 38

Kaemmer san

 

thank you very much for your advice. Indeed, my current obstacle at this moment is the reliability of my contact, which are still inconsistent depending on the measurements. 

I am trying to do some IV characterisitic of ZnO nanowire. 

I am a bit concerned about the DDESP type, as I don't know how the bandenedgy will bend, and what the schottky barrier would be, but I am sure there are bunch of articles outside.

 

the force is indeed very tricky, as my IV measurement changed considerably during the force/current measurement. According to the Veeco technician, the best way is to play around with the set point.

At the moment, I am applying 8N/m, which I think is very high pressure, considering the tip area. I don't know how this amount of force affects the measurement. If you know anything about it, all advice will be of a great help.

 

thank you very much again, sincerely

 

 

yuji 

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Bruker Employee

In addition to Stefan's advice, I've had some success with making repeatable IV curve measurements with these probes.

 

Jason.

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replied on Mon, Jul 19 2010 11:56 AM

I'll have to try a few of those. Thanks.

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thank you very much for your advice Jason

 

I had contacted these guys, so that I can see how the morphology imaging and IV characteristic would look like.

did you manage to get some good results??

 

 

thanks

 

 

Yuji

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For c-AFM I'd highly reccomend not using PPP-EFM.

While it's a great KPFM tip its built for tapping mode, so its got a stiffer spring constant and will be more prone to breaking under contact conditions.

Using any metal coated tip that is built for contact mode would give you more reproducible results

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Points 22

Dear Susuki San,

In private communication I could send you a paper work about electrical characterization on WO3 nanorods usign C-AFM which I hope it can help you.

If you wish, please send me your email address to do.

Regards.

Oscar

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replied on Wed, Aug 18 2010 5:40 PM

Hi Oscar,

Why don't you post the reference to your paper? This way it may be of help for a wider audience.

 

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Points 22

Hi Stefan,

 

You are right, the reference is Guiano et al., Surface Science, 601 (2007) 2684-2687.

 

Regards,

Oscar

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