High-speed tapping mode imaging with active Q control for atomic force microscopy

The speed of tapping mode imaging with the atomic force microscope (AFM) ha s been increased by over an order of magnitude. The enhanced operation is a chieved by (1) increasing the instrument's mechanical bandwidth and (2) act ively controlling the cantilever's dynamics. The instrument's mechanical ba ndwidth is increased by an order of magnitude by replacing the piezotube z- axis actuator with an integrated zinc oxide (ZnO) piezoelectric cantilever. The cantilever's dynamics are optimized for high-speed operation by active ly damping the quality factor (Q) of the cantilever. Active damping allows the amplitude of the oscillating cantilever to respond to topography change s more quickly. With these two advancements, 80 mu mx80 mu m high-speed tap ping mode images have been obtained with a scan frequency of 15 Hz. This co rresponds to a tip velocity of 2.4 mm/s. (C) 2000 American Institute of Phy sics. [S0003- 6951(00)02811-4].