Modeling and Analysis of an AlN Piezoelectric Micro-swimmer with Integrated Gold Electrodes

Abstract

Microscale robotics is expanding the possibilities for medicine, particularly in targeted drug delivery and in vivo diagnostics. Inspired by the natural propulsion mechanisms of microorganisms and recent advances in dislocation-driven growth shaping AlN's anisotropic morphology, this study explores a 2D model of an AlN piezoelectric micro-swimmer with integrated ultra-thin gold electrodes (0.045 μm) for controlled actuation and adaptability. The 2.89 μm AlN layer, combining stiffness and flexibility, harnesses piezoelectric effects to convert electrical energy into mechanical deformation. This deformation drives electric-induced kinematics, which, coupled with a closed-loop feedback control system, enables the micro-swimmer to demonstrate periodic motion, with potential for non-reciprocal actuation and navigation in low Reynolds number environments. The micro-swimmer's design features a multi-electrode configuration encapsulating the piezoelectric layer. Phase-shifted electric potentials and polarity differences across multiple electrodes produce alternating deformations. These dynamics are explored within a closed microchannel with pressure point constraints, as well as under a parabolic inlet velocity profile, revealing the swimmer's ability to resist flow-induced forces and maintain controlled motion. This study is simulated in a 2D environment due to computational limitations. To approximate and visualize potential 3D dynamics, an out-of-plane component was purposely selected. The study explores how parameters such as time-switch modulation, voltage control, and feedback mechanisms influence displacement and propulsion behavior. While achieving significant forward motion remains challenging, the swimmer exhibits controlled motion with potential for non-reciprocal actuation, contributing valuable insights into AlN micro-swimmer dynamics. These findings pave the way for future 3D simulations, such as a microhelix design, aimed at exploring AlN's robust piezoelectric characteristics, including the strong directional coupling along the z-axis, and efficient energy conversion, which are critical for effective propulsion. The insights gained from this study provide a foundation for subsequent investigations into the potential of AlN micro-swimmers for controlled navigation in microfluidic environments