Spectroscopy - Spectroscopy Spectroscopy allows several...

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Spectroscopy Spectroscopy allows several variables to be plotted with respect to each other at a single location of the sample. Click the Spectroscopy toolbar button to open the Spectroscopy Window and the Realtime Plots Window. The following spectroscopy plots are available: Force vs. Distance . In AFM Modes this plot shows the contact force between the sample and tip as a function of the vertical displacement of the tip. The vertical position of the tip is know from the calibrated voltage applied to the Z piezo, and the deflection of the cantilever is determined from the voltage output of the photodiode detector. The Force vs Distance curve, indicates the stiffness of the sample, when the stiffness of the cantilever is known. The spring constant of the cantilever can be determined using Thermal K . Current vs. Distance . In STM Mode this plot lets you measure the tunneling current between the STM tip and the sample surface as a function of the separation distance. The vertical position of the tip is know from the calibrated voltage applied to the Z piezo, and the tunneling current is measured at the preamp. The curve is therefore the tunneling current plotted as a function of the Z piezo voltage. Current vs. Bias . This plot shows the current flowing through the tip as a function of the electric potential applied between the tip and the sample. It shows a sample's conductivity at a location as a function of applied voltage. The cantilever is held in contact with the sample to create this plot. The current signal is measured at the preamp. Using Custom Spectroscopy you can define your own spectroscopy sweep, segment by segment. Main Tab Advanced Tab Custom Tab Thermal K Tab
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Spectroscopy Main Tab Plot Type Select one of the standard spectroscopy sweeps or create a custom sweep: Force vs Distance ( AFM Mode ): Deflection of the cantilever as a function of its vertical displacement. The blue line plot line indicated the tip's movement toward the sample, and the red line the movement away from the sample. The difference between these lines indicates the hysteresis of the cantilever and the adhesion forces between tip and sample. Current vs Distance ( STM Mode ): Displays the current flowing through the tip as a function of the vertical distance between tip and sample. Current vs Bias
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This note was uploaded on 09/08/2010 for the course MATE 145 at San Jose State University .

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Spectroscopy - Spectroscopy Spectroscopy allows several...

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