Zusammenfassung
The resolution of frequency modulation atomic force microscopy is limited by instrumental noise. When using a qPlus sensor, the deflection detector noise is the dominant noise contribution. It can be reduced by improving the preamplifier used to amplify the sensor deflection signal. We present a simple single-stage differential preamplifier which outperforms previous designs known to us by at ...
Zusammenfassung
The resolution of frequency modulation atomic force microscopy is limited by instrumental noise. When using a qPlus sensor, the deflection detector noise is the dominant noise contribution. It can be reduced by improving the preamplifier used to amplify the sensor deflection signal. We present a simple single-stage differential preamplifier which outperforms previous designs known to us by at least a factor of two in the deflection noise density. We show specific versions of this preamplifier to use in ambient conditions, in ultra-high vacuum at room temperature, and at 4.2 K. Furthermore, we compare the thermal peak analysis and the frequency shift noise density method as a means to determine the deflection noise density. We note that this preamplifier can also be used for any current-generating sensors such as other piezoelectric sensors and photodiodes, but, in this paper, we restrict our analysis to qPlus sensors. Published by AIP Publishing.
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