Thermally driven non-contact atomic force microscopy

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 2nm with long term separation stability (>30min). Employing this method a narrowband 250Hz modulation of the tip-sample separation was detected with a vertical resolution of 0.25A in a 0.4Hz 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.

[1]  Toyoaki Eguchi,et al.  High resolution atomic force microscopic imaging of the Si(111)-(7 x 7) surface: contribution of short-range force to the images. , 2002, Physical review letters.

[2]  Bielefeldt,et al.  Subatomic Features on the Silicon (111)-(7x7) Surface Observed by Atomic Force Microscopy. , 2000, Science.

[3]  Ahmet Oral,et al.  Quantitative atom-resolved force gradient imaging using noncontact atomic force microscopy , 2001 .

[4]  R. Erlandsson,et al.  Force interaction in low-amplitude ac-mode atomic force microscopy:. cantilever simulations and comparison with data from Si(111)7×7 , 1998 .

[5]  Hendrik Hölscher,et al.  Calculation of the frequency shift in dynamic force microscopy , 1999 .

[6]  A. Oral,et al.  A novel force microscope and point contact probe , 1993 .

[7]  Karoly Holczer.  Accelerated Development of a High Field Single Electron Spin Microscope , 2005 .

[8]  S. Jarvis,et al.  Direct mechanical measurement of interatomic potentials , 1996, Nature.

[9]  V. Pisarenko.  The Retrieval of Harmonics from a Covariance Function , 1973 .

[10]  Andrew E. Pelling,et al.  Local Nanomechanical Motion of the Cell Wall of Saccharomyces cerevisiae , 2004, Science.

[11]  A. Oral,et al.  Direct measurement of interatomic force gradients using an ultra-low-amplitude atomic force microscope , 2001, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[12]  Mark A. Lantz,et al.  Off resonance ac mode force spectroscopy and imaging with an atomic force microscope , 1999 .

[13]  D. Rugar,et al.  Frequency modulation detection using high‐Q cantilevers for enhanced force microscope sensitivity , 1991 .

[14]  Karol Putyera,et al.  Dekker Encyclopedia of Nanoscience and Nanotechnology , 2004 .

[15]  F. Giessibl.  Atomic Force Microscopy in Ultrahigh Vacuum , 1994 .