AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Wednesday Sessions
       Session NS+NANO6+MC-WeM

Paper NS+NANO6+MC-WeM2
Q-Control: Characterizing Highly Sensitive Surface Structures with the AFM

Wednesday, October 4, 2000, 8:40 am, Room 302

Session: Nanomechanical and Interface Measurements
Presenter: B. Anczykowski, NanoAnalytics WWU Münster, Germany
Authors: B. Anczykowski, NanoAnalytics WWU Münster, Germany
L.F. Chi, Physikalisches Institut WWU Münster, Germany
H. Fuchs, Physikalisches Institut WWU Münster, Germany
Correspondent: Click to Email
When operating an atomic force microscope (AFM) in a dynamic mode the oscillation of the cantilever is influenced by non-linear interaction forces between the probing tip and the surface. In principle the instantaneous forces exerted on the sample while scanning the surface can be either repulsive or attractive. Experimental findings and corresponding computer simulations of the tapping mode show that by choosing appropriate system parameters the AFM can continuously be operated in the regime of net-attractive interaction forces. Thereby the risk of modifying the sample surface by the probing tip is minimized. However, in most cases the range in which the system parameters have to be adjusted is rather narrow and therefore a stable operation of the AFM in this interaction regime is difficult to achieve. With the help of the Q-Control module it is possible to reduce the damping of the dynamic system, i.e. to increase the effective quality factor of the oscillating cantilever and thereby to enlarge the regime of net-attractive interaction forces.@footnote 1@ This method allows to minimize the forces exerted by the probing tip on the sample surface. Therefore by applying Q-Control delicate and highly sensitive surfaces, such as ultrathin organic layers or DNA structures, can be characterized with high resolution. @FootnoteText@ @footnote 1@B. Anczykowski, J. P. Cleveland, D. Krüger, V. B. Elings, and H. Fuchs, Appl. Phys. A 66, S885 (1998).