Surface contamination-induced resonance frequency shift of cantilevers

Nanoelectromechanical cantilevers have achieved unprecedented sensitivity in the detection of displacement, mass, force and charge. Although resonating cantilevers are demonstrated to be excellent mass sensors, environmental effects like humidity, ambient gases and contamination result in uncertainty in the calculation of either adsorbed mass or mechanical properties due to shifts in resonance frequencies. In this work the resonance frequency shift due to surface contamination has been studied. Single crystalline silicon (SCS) cantilevers of various dimensions (1025, 340, and 93 nm-thick) were fabricated and their resonance frequencies due to thermal noise were measured in air and in low vacuum. A resonance frequency shift was seen in air after keeping the samples in vacuum. Our measurement shows that this shift comes from surface contamination. The thinner cantilever showed more sensitive behavior to the air conditions. These results can be used to decrease the errors in the calculation of adsorbed mass and mechanical properties of nanostructures. The calculated equivalent mass-induced resonance frequency shifts of our experiments were measured to be 183×10−15 gram (183 femtogram) and a mass sensitivity of about 6.5×10−18 g/Hz (6.5 ag/Hz) was obtained. Our results and analysis indicate that mass sensing of individual molecules will be realizable when taking into account the surface contamination

[1]  Hiroyuki Fujita,et al.  Millions of cantilevers for atomic force microscopy , 2002 .

[2]  Takashi Izumi,et al.  Femtogram Mass Biosensor Using Self-Sensing Cantilever for Allergy Check , 2006 .

[3]  K.E. Petersen,et al.  Silicon as a mechanical material , 1982, Proceedings of the IEEE.

[4]  M. Roukes,et al.  Ultrasensitive nanoelectromechanical mass detection , 2004, cond-mat/0402528.

[5]  M. Roukes,et al.  Fabrication of high frequency nanometer scale mechanical resonators from bulk Si crystals , 1996 .

[6]  M. Roukes.  Nanoelectromechanical Systems , 2000, cond-mat/0008187.

[7]  Sumio Hosaka,et al.  Picogram Mass Sensor Using Resonance Frequency Shift of Cantilever , 2004 .

[8]  E. A. Wachter,et al.  Detection of mercury vapor using resonating microcantilevers , 1995 .

[9]  H. Craighead.  Nanoelectromechanical systems. , 2000, Science.

[10]  Patrick J. French,et al.  Effects of Surface Stress on Nanocantilevers , 2009 .

[11]  M. Roukes,et al.  Zeptogram-scale nanomechanical mass sensing. , 2005, Nano letters.

[12]  Masayoshi Esashi,et al.  Surface effects and high quality factors in ultrathin single-crystal silicon cantilevers , 2000 .

[13]  Panos G. Datskos,et al.  Femtogram mass detection using photothermally actuated nanomechanical resonators , 2003 .

[14]  M. Calleja,et al.  Detection of bacteria based on the thermomechanical noise of a nanomechanical resonator: origin of the response and detection limits , 2008, Nanotechnology.

[15]  Hiroyuki Fujita,et al.  Towards atomic force microscopy up to 100 MHz , 2002 .

[16]  Amit K. Gupta,et al.  Single virus particle mass detection using microresonators with nanoscale thickness , 2004 .

[17]  M. Roukes.  Nanoelectromechanical systems face the future , 2001 .

[18]  M. Grattarola,et al.  Micromechanical cantilever-based biosensors , 2001 .