Design Rules for Nanogap‐Based Hydrogen Gas Sensors

Nanoscale gaps, which enable many research applications in fields such as chemical sensors, single‐electron transistors, and molecular switching devices, have been extensively investigated over the past decade and have witnessed the evolution of related technologies. Importantly, nanoscale gaps employed in hydrogen‐gas (H 2 ) sensors have been used to reversibly detect H 2 in an On–Off manner, and function as platforms for enhancing sensing performance. Herein, we review recent advances in nanogap design for H 2 sensors and deal with various strategies to create these gaps, including fracture generation by H 2 exposure, deposition onto prestructured patterns, island formation on a surface, artificial manipulation methods, methods using hybrid materials, and recent approaches using elastomeric substrates. Furthermore, this review discusses a new nanogap design that advances sensing capabilities in order to meet the diverse needs of academia and industry.