title: Digitally tunable, wide-band amplitude, phase, and frequency detection for atomic-resolution scanning force microscopy.
abstract: Frequency-modulation atomic force microscopy (FM-AFM) relies on an accurate tracking of the resonance frequency of a scanning probe. It is now used in environments ranging from ultrahigh vacuum to aqueous solutions, for slow and for fast imaging, with probes resonating from a few kilohertz up to several megahertz. Here we present a versatile experimental setup that detects amplitude, phase, and frequency of AFM probes for resonance frequencies up to 15 MHz and with >70 kHz maximum bandwidth for amplitude/phase detection. We provide generic parameter settings for variable-bandwidth frequency detection and test these using our setup. The signal-to-noise ratio of the frequency detector is sufficiently high to record atomic-resolution images of mica by FM-AFM in aqueous solution.
authors.affiliation: London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, United Kingdom.
authors.forename: Z
authors.initials: Z
authors.lastname: Khan
authors.forename: C
authors.initials: C
authors.lastname: Leung
authors.forename: B A
authors.initials: BA
authors.lastname: Tahir
authors.forename: B W
authors.initials: BW
authors.lastname: Hoogenboom
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D004867:Equipment Design; D018625:Microscopy, Atomic Force / Q000295:instrumentation / Q000379:methods*; D011846:Radio Waves; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; C011934:mica