ENGRI_111_SFM - Atomic Resolution Model of Si surface...

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ENGRI_111 10/18/2004 Atomic Resolution Model of Si surface 2.7 nm Imaged in STM at Cornell Tungsten tip +2 V on sample, 1 nA
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ENGRI_111 10/18/2004 Scanning Probe Microscopy Technology Basic Instrumentation Vibration Isolation •Internal spring systems •Rigid, compact design •External air pistons Nanometer Scanner •Piezoceramic tubes, rods •Hysteresis unavoidable Sample Approach Nanometer steps over mm distances! •Mechanical screws •Piezoceramic actuators Vintage 1988 STM
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ENGRI_111 10/18/2004 Movement of cantilever is monitored, usually by bouncing a laser off the back of the cantilever into a detector. Depending of the ”softness” of the cantilever, SFM can detect forces ~ 100 pN Scanning Force Microscopy (SFM) Scanning Force Microscopy (SFM) When the cantilever ”hits” an object it will bend and the deflection of the laser will be detected by the photo detector
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ENGRI_111 10/18/2004 How does it work? How does it work? The signal from the photodetector is used to keep a constant force by changing the tip-sample distance This results in a topographical image of the surface
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ENGRI_111 10/18/2004 SFM: Contact Mode
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This homework help was uploaded on 02/03/2008 for the course ENGRI 1110 taught by Professor Giannelis during the Fall '07 term at Cornell University (Engineering School).

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ENGRI_111_SFM - Atomic Resolution Model of Si surface...

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