Session U38: Focus Session: Advances in Scanned Probe Microscopy III: High Frequency and Probe Characterization

8:00 AM–11:00 AM, Thursday, March 8, 2007
Colorado Convention Center Room: 501

Sponsoring Unit: GIMS
Chair: Eric Hudson, Massachusetts Institute of Technology

Abstract ID: BAPS.2007.MAR.U38.2

Abstract: U38.00002 : Very high frequency (VHF) self-sensing nanoscale cantilevers and their mass sensing applications in ambient conditions.

8:12 AM–8:24 AM

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  Mo Li
    (Kavli Nanoscience Institute and Department of Applied Physics, California Institute of Technology)

  Hong Tang
    (Kavli Nanoscience Institute and Department of Physics, California Institute of Technology)

  Michael Roukes
    (Kavli Nanoscience Institute and Departments of Physics, Applied Physics, and Bioengineering, California Institute of Technology)

We report the development a new class of self-sensing, nanometer-scale cantilevers with fundamental-mode mechanical resonances up to very high frequencies (VHF). The sensors employ integrated piezoresistive displacement transducers; we show that, at the nanoscale, these are optimally realized using thin, metallic-density films. Our approach enables detection of VHF cantilever vibrations, to date as high as 127 MHz, at the thermomechanical noise limit. Displacement sensitivity of 39 fm/Hz$^{1/2}$ and extremely low 1/f noise are attained. Our smallest devices have lateral dimensions approaching the mean free path at atmospheric pressure; hence their high quality factors are preserved in ambient. Measurements of molecular chemisorption onto polymer-coated nanocantilevers yield unprecedented mass resolution below 1 attogram (10$^{-18}$ g) level at atmospheric pressure and room temperature.

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