Plasmon-Induced Graphene/Silicon Schottky Junctions for Ultrasensitive Gas Sensing.

Modulating metal oxide-based gas sensors with light is emerging as an alternative to enhance their sensitivity and selectivity. Plasmonic gas sensors based on excitation of the localized surface plasmon resonance (LSPR) in noble metals have recently shown promising properties. The classic approach of incorporating LSPR in sensors is to measure changes in the optical properties of the plasmonic material that depend on the surrounding local environment, i.e., an optical sensor device. The less common approach is to utilize chemiresistive sensors that consist of a gas-sensitive material (like graphene) decorated with plasmonic nanoparticles and employ solely electrical measurements for sensing data acquisition. This work demonstrates a chemiresistive gas sensor graphene/silicon Schottky junction decorated with palladium nanoparticles (PdNPs) that exhibit LSPR in the UV light range. We demonstrate a method of recording responses of plasmonic gas sensors based only on their DC characteristic measurements, which is simplified compared to optical and spectroscopic methods. Supported by the DC characteristics recorded under different UV wavelengths (255 nm, 275 nm, 355 nm), we show that the highest sensitivity to NO