Abstract
In this letter a thermally driven frequency modulated atomic force microscopy (FM-AFM) technique is developed. Thermal fluctuations of the cantilever are employed to estimate the cantilever's equivalent resonant frequency. The corresponding cantilever oscillations are the smallest possible at a given temperature. Related experiments that establish the feasibility of thermally driven FM-AFM in ambient room conditions have achieved tip-sample separations less than 2 nm with long term separation stability (>30 min). Employing this method a narrowband 250 Hz modulation of the tip-sample separation was detected with a vertical resolution of 0.25 Å in a 0.4 Hz bandwidth. The corresponding estimated force sensitivity is 7 fN. In all experiments the cantilever tip was maintained in the attractive regime of the tip-sample interactions. This demonstrates a thermally driven non-contact mode operation of AFM. It also provides a limits of performance study of small amplitude FM-AFM methods.
Original language | English (US) |
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Article number | 111901 |
Journal | Applied Physics Letters |
Volume | 87 |
Issue number | 11 |
DOIs | |
State | Published - Sep 12 2005 |
Bibliographical note
Funding Information:M.S. acknowledges the support from the NSF Grant ECS-0330224.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.