When 3:30 PM - 5:00 PM Feb 24, 2012
Where 1670 CSE Building
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Designing Piezoelectric Films for Microelectromechanical Systems (MEMS)


Susan Trolier-McKinstry
Pennsylvania State University, Materials Science and Engineering

Piezoelectric thin films are of increasing interest in low voltage microelectromechanical systems for sensing, actuation, and energy harvesting.  They also serve as model systems to study fundamental behavior in piezoelectrics.  Next generation technologies such as ultrasound pill cameras, flexible ultrasound arrays, and energy harvesting systems for unattended wireless sensors will all benefit from improvements in the piezoelectric properties of the films. This presentation will describe tailoring the composition, microstructure, orientation of thin films, and substrate choice in order to optimize the response. In some cases, improvements in the figure of merit of up to a factor of 10 has been achieved. To improve our fundamental understanding of the evolution of the properties with thickness and mechanical boundary conditions, band excitation piezoelectric force microscopy was used to interrogate the nonlinearity locally.  It was found that PbZr0.52Ti0.48O3 thin films show clusters of larger nonlinear response embedded in a more weakly nonlinear matrix.  The scale of the clusters significantly exceeds that of the grain size, suggesting that collective motion of many domain walls contributes to the observed Rayleigh behavior in these films.  Finally, approaches to lower processing temperatures will be described through the use of pulsed laser annealing.

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