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A sensitive volatile organic vapor sensor based on the LSPR properties of silver triangular nanoprisms is proposed in this paper. The triangular nanoprisms were fabricated by a nanosphere lithography (NSL) method. They have sharp vertices and edges, and are arranged in an ideal hexangular array. These characteristics ensure that they exhibit an excellent LSPR spectrum and a high sensitivity to the exterior environment changes. The LSPR spectra responding to ethanol vapor and four other volatile organic vapors—acetone, benzene, hexane and propanol—were measured with a UV-vis spectrometer in real time. Compared with the other four vapors, ethanol exhibits the highest sensitivity (∼0.1 nm/mg L−1) and the lowest detection limit (∼10 mg/L) in the spectral tests. The ethanol vapor test process is also fast (∼4 s) and reversible. These insights demonstrate that the triangular nanoprism based nano-sensor can be used in ethanol vapor detection applications.

A microelectromechanical system (MEMS) spring actuator based on the electrostatic repulsive force is presented. In general, an electrostatic-attractive-force-based actuator has a small stroke because instability results from the electrostatic pull-in effect. Therefore, a great deal of effort has been made to achieve large strokes for various applications. Based on the fact that an asymmetric electric field can produce an electrostatic repulsive force, an out-of-plane actuator has been demonstrated in this paper. The actuator consists of two layers which are parallel to each other. The top layer contains a central mass with a size of 100 μm × 100 μm × 2 μm, and it is suspended by a folding spring. The second layer is fixed to the substrate and works as the bottom electrodes of the actuator. The impacting factors to the repulsive force which consequently affect the displacement of the actuator are analyzed using finite element analysis software, and the optimal structure parameters have been obtained. The actuator is fabricated by the poly-multi-user-MEMS-process (PolyMUMPs); the measured out-of-plane displacement of this actuator reaches 2.7 μm at 50 V dc, and it shows good agreement with the simulation.