Hydrogen Induced Dipole Layer in Pd-SiO2 Based Gas Sensors

A palladium (Pd) functionalized electrostatically formed nanowire (EFN) sensor, a silicon-on-insulator (SOI) based multi-gate transistor, has proven to be an ultra-sensitive platform for hydrogen (H-2) sensing. This EFN includes a PdSiO2-Silicon, a metal-oxide-semiconductor (MOS) structure which is studied here in detail. We compare the EFN threshold voltage shift (Delta V-TH) due to H-2 adsorption, to the calculated.VTH due to dipoles placed at the Pd/SiO2 interface of the EFN device. We show that the potential drop at the Pd/SiO2 interface is responsible for the ultra-sensitive hydrogen sensing of the EFN.