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Abstract Zero‐standby power sensors are crucial for enhancing the safety and widespread adoption of hydrogen (H₂) technologies in chemical processes and sustainable energy applications, given the flammability of H₂at low concentrations. Here, we report an event‐driven hydrogen sensing system utilizing palladium (Pd)‐based micromechanical cantilever switches. The detection mechanism relies on strain generation in the Pd layer, which undergoes reversible volume expansion upon hydrogen adsorption. Our experimental and simulation results demonstrate that the bistable micromechanical switch‐based sensor generates a wake‐up signal with activation time depending on hydrogen concentration in the target environment while always remaining active for events without any standby power consumption under normal conditions. The H₂adsorption‐induced subsequent switching of the multi‐cantilever‐based switch configuration on the sensor resulted in the quasi‐quantification of hydrogen concentrations. The reported zero‐standby power sensor's operational lifetime is limited by the frequency of detection events and exposure to concentrations exceeding hydrogen's flammability limit. This work advances the development of high‐density, maintenance‐free sensor networks for large‐scale deployment with Internet of Things devices, enabling unattended continuous monitoring of hydrogen generation, transportation, distribution, and end‐user applications. 

The patterning of silicon and silicon oxide nanocones onto the surfaces of devices introduces interesting phenomena such as anti-reflection and super-transmissivity. While silicon nanocone formation is well-documented, current techniques to fabricate silicon oxide nanocones either involve complex fabrication procedures, non-deterministic placement, or poor uniformity. Here, we introduce a single-mask dry etching procedure for the fabrication of sharp silicon oxide nanocones with smooth sidewalls and deterministic distribution using electron beam lithography. Silicon oxide films deposited using plasma-enhanced chemical vapor deposition are etched using a thin alumina hard mask of selectivity > 88, enabling high aspect ratio nanocones with smooth sidewalls and arbitrary distribution across the target substrate. We further introduce a novel multi-step dry etching technique to achieve ultra-sharp amorphous silicon oxide nanocones with tip diameters of ~10 nm. The processes presented in this work may have applications in the fabrication of amorphous nanocone arrays onto arbitrary substrates or as nanoscale probes.