Palladium/silicon nanowire Schottky barrier-based hydrogen sensors

Abstract

a b s t r a c tThis work presents the design, fabrication, and characterization of a hydrogen sensor based on a palladium/nanowire Schottky barrier field-effect transistor that operates at room temperature. The fabricated sensor consists of boron-doped silicon nanowire arrays that are contact printed on top of a SiO 2 /Si substrate with subsequently evaporated Pd contacts. The fabrication process is compatible with post-CMOS and plastic substrate integration as it can be completed at temperatures below 150• C with good yield and repeatability. The sensor can reliably and reversibly detect H 2 concentrations in the range from 3 ppm to 5% and has a sensitivity of 6.9%/ppm at 1000 ppm. A response distinguishable from drift and noise is produced in less than 5 s for H 2 concentrations over 1000 ppm and less than 30 s for concentrations over 100 ppm. The sensor settles to 90% of the final signal value in about 1 h at lower concentrations and less than 1 min at 10,000 ppm H 2 . Drift over an 87-h measurement period is below 5 ppm H 2 concentration.

Recent advances in large-scale assembly of semiconducting inorganic nanowires and nanofibers for electronics, sensors and photovoltaics

“…For example, p-type Si-nanowire arrays were configured as H 2 sensors. 173 To enhance sensitivity to H 2 , a 2 nm-thick Pd film was deposited on the printed nanowire array, resulting in the formation of Pd nanoclusters on the nanowire surfaces. It is found that the conductance of the Si-nanowire array shows a strong dependence on the H 2 exposure, even at relatively low concentrations (250 ppm).…”

MoS2 P-type Transistors and Diodes Enabled by High Work Function MoOx Contacts

“…Traditionally, the high work function metal palladium (Pd) has been used as the most popular contact material to the valence band of various nanostructures, including nanotubes, graphene, and organics [7] [8] [9] [10]. However Pd alone has proven insufficient as a hole contact for TMDC devices.…”

Ultrasensitive detection of low-ppm H2S gases based on palladium-doped porous silicon sensors

“…Pd particles are mainly used as H 2 sensing materials and form PdH x upon exposure to H 2 gas molecules through dissociative adsorption, resulting in changes in the resistance of the substrate. 28 It is extensively used as a catalyst metal for the enhancement of H 2 S gas adsorption over a wide range of temperatures and enables detection even at room temperature. 29,30 Hydrogen sulde gas also shows dissociative adsorption at the surface of the catalytic Pd clusters, then diffuses before interacting with other reacting adsorbate oxygen species in atmospheric conditions.…”