Starting small: Advance could set piezoelectric material applications in motion

Posted on 19. Apr, 2012 by in Academic Departments, Issues, Magazine, Materials Science and Engineering, Research

Piezoelectric cantilever imageIntegrating a complex, single-crystal material with “giant” piezoelectric properties onto silicon, UW-Madison engineers and physicists can fabricate low-voltage, near-nanoscale electromechanical devices that could lead to improvements in high- resolution 3-D imaging, signal processing, communications, energy harvesting, sensing, and actuators for nanopositioning devices, among others.

Led by Harvey D. Spangler Distinguished Professor of Materials Science and Engineering and Physics Chang-Beom Eom, the multi-institutional team published its results in the November 18, 2011, issue of the journal Science.

Piezoelectric materials use mechanical motion to generate an electrical signal—or they can use an electrical signal to generate mechanical motion—for example, to generate high-frequency acoustic waves for ultrasound imaging. A major limitation of these advanced materials is that to incorporate them into very small devices, researchers start with a bulk material and grind, cut and polish it to the size they desire. It’s an imprecise, error-prone process that’s intrinsically ill-suited for nano- or microelectromechanical systems.

Eom studies the advanced piezoelectric material lead magnesium niobate-lead titanate, or PMN-PT. Until now, its complexity has thwarted researchers’ efforts to develop simple, reproducable microscale fabrication techniques. Applying microscale fabrication techniques such as those used in computer electronics, Eom’s team has overcome that barrier.  “The properties of the single crystal we integrated on silicon are as good as the bulk single crystal,” says Eom.

His team also developed a method for fabricating piezoelectric microelectromechanical systems. Applied in signal processing, communications, medical imaging and nanopositioning actuators, those systems could reduce power consumption and increase actuator speed and sensor sensitivity.
Additionally, through a process called energy harvesting, they could convert energy from sources such as mechanical vibrations into electricity that powers other small devices—for example, for wireless communication.

Read a longer version of this story here.Bucky Badger head

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