Nanowatt chemical vapor detection with a self-sensing, piezoelectric microcantilever array

Abstract

The portability, compactness, price, and deployment of sensing systems are determined in large part by the power consumption and simplicity of the sensing platform used. We demonstrate a microcantilever chemical detection platform based on an array of piezoelectric microcantilevers. The sensor-element array power consumption, including actuation, is measured in nanowatts, with impedance of the order of megohms. This is four to five orders of magnitude lower power dissipation than current cantilever chemical detection platforms using optical or piezoresistive detection. The sensor is further characterized in the picowatt regime. The platform comprises three cantilevers wired in series, where variations in the resonant frequency and quality factor of selectively coated cantilevers, during successive impedance measurements, enable detection of ethanol vapor.

Effect of Coating Viscoelasticity on Quality Factor and Limit of Detection of Microcantilever Chemical Sensors

“…This provides the motivation to consider a first-order approximation to (9) and (11) as (12) (13) Equation (13) clearly shows that the quality factor due to coating losses decreases with increasing coating thickness. In the case of a small coating thickness , the same expression as that of surface losses developed in [10] and [17] is found.…”

“…1). The absorbed molecules can then be detected by monitoring the shift in the mechanical resonant frequency [1]- [9].…”

Nonlinear mathematical modeling of vibrating motion of nanomechanical cantilever active probe

“…Other advantages of this type of NMCs are compacting of AFM when the NMCs are used as a sensor, and the possibility of using multiple probes in parallel functions (Adams et al, 2003) The accuracy of power estimation based on AFM measured information depends on the selected dynamic model for the cantilever. With its effect on the controlling system, dynamic system model directly affects the images resolution.…”

Electrical detection of the mechanical resonances in AlN-actuated microbridges for mass sensing applications

“…5 Among the different ways used to produce the movement of the freestanding microstructures, piezoelectric actuation offers the advantage of low actuation voltages and moderate power consumptions. 6 Piezoelectric flexural resonators are based on the mechanical bending experienced by unimorph structures ͑piezoelectric/structural layer͒ when an external field perpendicular to the surface is applied. The electric field induces a longitudinal extension ͑or contraction͒ of the piezoelectric layer, proportional to the piezoelectric coefficient d 31 .…”