Palladium/single-walled carbon nanotube back-to-back Schottky contact-based hydrogen sensors and their sensing mechanism.

A Schottky contact-based hydrogen (H2) gas sensor operable at room temperature was constructed by assembling single-walled carbon nanotubes (SWNTs) on a Si/SiO2 substrate bridged by Pd microelectrodes in a chemiresistive/chemical field effect transistor (chemFET) configuration. The Schottky barrier (SB) is formed by exposing the Pd-SWNT interfacial contacts to H2 gas, the analyte it was designed to detect. Because a Schottky barrier height (SBH) acts as an exponential bottleneck to current flow, the electrical response of the sensor can be particularly sensitive to small changes in SBH, yielding an enhanced response to H2 gas.