Here we report a new nanogap formation manner at edges of a palladium (Pd) thin film on highly patterned arrays of an elastomeric PDMS substrate fabricated nanoimprint lithography (NIL) by absorption/desorption cycles of H2 for use in the detection of hydrogen (H2) gas. A 10-nm-thick Pd layer was deposited on the patterned PDMS substrate using an ultra-high vacuum DC magnetron sputtering system. The Pd nanogaps (∼100 nm (W)) formed on the edges of the grating structure by expansion and contraction of the film through a few cycles of H2 absorption and desorption. Such nanogaps are crucial to the performance of the sensors. The H2 sensors were found to exhibit a fast response time (∼1 s), low detection limit (0.1%), wide linear range (0.1-2%), and an ON-OFF switching operation in air. These properties are attributed to the synergistic combination of nanogap break junction control in Pd and the patterned elastomeric substrate.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry