The Nanoscale World

drifting in successive height scans

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Eric posted on Wed, Aug 29 2012 9:25 PM

Hello,

 

We have an Innova SPM and have it setup to do scattering NSOM measurements simultaneously while the microscope is in Tapping AFM mode.  The area under the tip gets excited with an IR laser and we use the tip to scatter off the near-field signal.  The problem we encounter is x, y drift, which really seems to affect the quality of the data because the structures we are analyzing move around the image on successive scans and we use successive NSOM scans to extract out data that is positionally sensitive.  Basically, we take a series of the successive NSOM scans and run a point by point fit to extract out the data we are interested in.  It seems like if there is drift than we are not really fitting the same point in each image...  

 

Anyways, I was wondering if anyone knows of a matlab script that can correct drift in a height image (using one image as a reference) AND that can apply that same correction to corresponding images that are taken in parallel (the NSOM image basically).  I saw that WSXM5 can align several height images at once, which achieves 1/2 of what we want to do (what a great program!).  Any help would be greatly appreciated!  Thanks!

 

-Eric (UNC-Charlotte) 

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replied on Mon, Sep 17 2012 5:14 PM

Hi Eric,

The info on the NanoDrive file format is already on here. What do you do to minimize drift? Is your room temperature stable?

Stefan

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Eric replied on Mon, Sep 17 2012 6:00 PM

Hey Stefan,

 

Thanks for your response.  We don't do anything special to stabilize temperature.   The room temperature is under thermostat control and it seems to be pretty stable.  We have tried lowering the scan rate from 1.5Hz to 1Hz to minimize drift, but it doesn't seem to have  a signficant impact.  We do suspect that the tip gets heated up from the CO2 laser.  

 

-Eric

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Ang Li replied on Thu, Sep 27 2012 7:47 AM

if only tip heated up, you would see setpoint drift or z scanner drift, but if it's xy drift, I guess it is quite possible your sample is heated up.

Ang Li

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replied on Thu, Sep 27 2012 7:54 AM

It for sure will be the tip and sample that gets heated. The diffraction limited spot from the IR laser is so big that it will cover both tip and sample. 

I checked but unfortunately to this point could not find any software routine that would help you with the drift correction. 

Stefan

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