Experimental Investigation of Photostrictive Materials for MEMS Application

摘要

Micro-Electro-Mechanical-Systems (MEMS) is an emerging technology that integrates micromachined mechanical structures with integrated circuits (IC). During the last two decades, it has grown vastly as a prominent research area among scientists and engineers. Usually the main components of MEMS are sensors, actuators, and structures with all in microscale. A photostrictive mate-rial has high potential to be used in a MEMS application to develop an ad-vanced optical actuator. A strain is induced when a photostrictive material is il-luminated by high intensity light, which is known as photostriction. This phe-nomenon can be generally described as the combined effect of the photovoltaic effect and the converge-piezoelectric effect. When an incident light strikes a photostrictive material, a photovoltage is produced and this photovoltage develops strain in the material. Lanthanum modified lead zirconate titanate (Pb, La) (Zr, Ti) O3 ceramic doped with WO3, called PLZT, is one of the photostrictive ceramics which has an advantageous use as a wireless remote control over traditional actuators. Traditional actuators require wire connections to transmit the control signal; these wires yield noise via external electromagnetic fields. Whereas, PLZT actuators can transmit the control signal without wires which can eliminate possible noise due to the external electromagnetic field. In this current research, the photostrictive effect of a thin PLZT film on a silicon wafer is investigated experimentally. The transverse deflection of the PLZT optical actuator cantilever beam has been measured for stationary continuous light as well as for pulses of light using an optical chopper at various light intensities and focused locations. Results indicate that transverse deflection increases with the increase of light intensity. Also, the maximum transverse deflection at the free end of the cantilever beam for stationary light has been found to be three times larger than that for the pulses of light.