A Platinum Nanowire Sensor for Ethylene in Air

Abstract

A single platinum nanowire (PtNW) chemiresistive sensor for ethylene gas is reported. In this application, the PtNW performs three functions: (1) Joule self-heating to a specified temperature, (2) in situ resistance-based temperature measurement, and (3) detection of ethylene in air as a resistance change. Ethylene gas in air is detected as a reduction in nanowire resistance by up to 4.5% for concentrations ranging from 1 to 30 ppm in an optimum NW temperature range from 630 to 660 K. This response is rapid (30−100 s), reversible, and reproducible for repetitive ethylene pulses. A threefold increase in signal amplitude is observed as the NW thickness is reduced from 60 to 20 nm, commensurate with a signal transduction mechanism involving surface electron scattering.

Pd Decoration with Synergistic High Oxygen Mobility Boosts Hydrogen Sensing Performance at Low Working Temperature on WO3 Nanosheet

“…To obtain further information on the H 2 sensing process, the dynamic sensing response of the fabricated sensors was investigated. The energy barrier ( E a ) that H 2 oxidation reaction had to overcome, as illustrated in the equation t R e s p / R e c = τ 0 .25em e false( − E a / K B T false) where t Resp/Rec refers to the response/recovery time of the H 2 sensing process; τ 0 refers to the pre-exponential constant, E a is the apparent activation energies; K B refers to the Boltzmann constant (1.38 × 10 –23 J/K); and T is the reaction temperature. − The E a (response/recovery) values of Pd-WO 3 - x ( x = 200, 300, 400) were calculated to be 84.88/85.55, 48.41/49.17, and 77.82/67.8 meV, respectively (Figure ). In particular, Pd-WO 3 -300 exhibited the lowest activation energy barrier, which was consistent with the much higher surface reactivity of the Pd-WO 3 interface with H 2 .…”

Thermal-aware device design of low-power H2S sensors using Joule-heated Au nanosheet

“…Joule-heating is attracting attention as a low-power method for gas sensors using MOS nanowires 13,14) and other conductive nanoscale materials such as carbon nanotubes (CNT), 15) graphenes, 16,17) and metal nanosheets. 18,19) By using Joule heat generated by high current density through a conductive material, only the sensing part can be locally heated, which is much more efficient than an external heater that heats the entire substrate. In addition, Joule heating is advantageous for sensor integration because the multiple sensors can be adjusted to the optimum temperatures for each device by changing the applied voltage for each device and target gas.…”

Detection of PPB-Level H2S Concentrations in Exhaled Breath Using Au Nanosheet Sensors with Small Variability, High Selectivity, and Long-Term Stability

“…In this study, we utilized metal nanosheets as gas sensors. , The sensing mechanism of the metal nanosheet gas sensor is that the chemisorption of gas molecules on the metal surface changes the nanosheet resistance, while the physisorption hardly affects its resistance. − Since the chemisorption is based on the catalytic reaction, it can be highly selective to the specific gas molecules by properly selecting the metals . Furthermore, in a metal nanosheet gas sensor, the metal itself works not only as a receptor of the target gas but also as a transducer of chemisorption phenomena into electrical signals.…”