Information on STS ramp (nanoscope V 8.10)

Din posted on Fri, Sep 2 2011 10:47 AM

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We recently bought a Nanoscope V multimode SPM and we operate a separate STM base and a scanner head with the new controller box (software: nanoscope 8.10).  Previously we operated the STM with Nanoscope III controller (software: nanoscope 5.12r4).  With the new system, there are few things that I need to verify and I sincerely hope someone could help me with this.  The questions I have are mainly about the STS ramp. 

To get STS i(V) curves, these were some of the settings I used before; Feedback type: pixel,  Feedback counts: 1,  Feedback value: 0 mV,  Average counts: 20.  These setting allowed me to get nice STS i(V) curves of HOPG and SWNTs.

However, with the new software, if I put Feedback type as 'pixel' it gives out weird curves. But if I select 'cycle' as shown in the manual, it gives me reasonable I-V curves.  And also, in the manual it shows an example with Feedback count: 2000 and Feedback value: 100 mV.  I don't know what values I should use. Could somebody give me an example for HOPG?

Also, the I-V curves I’m getting (when I select ‘continuous’) change drastically.  Is this because of low image quality? Would lowering the ramp rate help?

Any feedback on this would be greatly appreciated !

Thank you,

Dinushi