title: Adaptive Q control for tapping-mode nanoscanning using a piezoactuated bimorph probe.
abstract: A new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q factor of an AFM probe. The Q factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using standard Q control is not possible. In adaptive Q control, the Q factor of the probe is set to an initial value as in standard Q control, but then modified on the fly during scanning when necessary to achieve this goal. In this article, we present the basic theory behind adaptive Q control, the electronics enabling the online modification of the probe's effective Q factor, and the results of the experiments comparing three different methods: scanning (a) without Q control, (b) with standard Q control, and (c) with adaptive Q control. The results show that the performance of adaptive Q control is superior to the other two methods.
authors.affiliation: College of Engineering, Koc University, Istanbul, Turkey.
authors.forename: Ihsan
authors.initials: I
authors.lastname: Gunev
authors.forename: Aydin
authors.initials: A
authors.lastname: Varol
authors.forename: Sertac
authors.initials: S
authors.lastname: Karaman
authors.forename: Cagatay
authors.initials: C
authors.lastname: Basdogan
mesh_terms: D002138:Calibration; D007834:Lasers; D018625:Microscopy, Atomic Force / Q000379:methods / Q000592:standards; D014732:Vibration