Characterization of Work per Volume Density of VO₂-Based MEMS Actuators

Vanadium dioxide (VO₂)-coated silicon microcantilevers have gained attention due to the large stress produced during VO₂’s thermally induced metal-to-insulator phase transition, which produces a curvature change of over ∼2,000 m⁻¹. Work per volume density is an important figure of merit used to compare the performance of smart materials in micro-actuation. In this paper, the work per volume density of five fully actuated VO₂-coated microcantilevers was calculated based on experimentally measured force vs. displacement curves obtained from an AFM operated in contact mode. The work per volume density for the five microactuators was found to be similar, which is around ∼1.5×10⁴ J/m³. The work per volume density of a single microactuator was also obtained under different temperatures across the material’s transition, which exhibits the hysteretic behavior during the heating-cooling cycle.