Wafer‐Level Manufacturing of MEMS H₂ Sensing Chips Based on Pd Nanoparticles Modified SnO₂ Film Patterns

Abstract

In this manuscript, a simple method combining atomic layer deposition and magnetron sputtering is developed to fabricate high‐performance Pd/SnO2 film patterns applied for micro‐electro‐mechanical systems (MEMS) H2 sensing chips. SnO2 film is first accurately deposited in the central areas of MEMS micro hotplate arrays by a mask‐assistant method, leading the patterns with wafer‐level high consistency in thickness. The grain size and density of Pd nanoparticles modified on the surface of the SnO2 film are further regulated to obtain an optimized sensing performance. The resulting MEMS H2 sensing chips show a wide detection range from 0.5 to 500 ppm, high resolution, and good repeatability. Based on the experiments and density functional theory calculations, a sensing enhancement mechanism is also proposed: a certain amount of Pd nanoparticles modified on the SnO2 surface could bring stronger H2 adsorption followed by dissociation, diffusion, and reaction with surface adsorbed oxygen species. Obviously, the method provided here is quite simple and effective for the manufacturing of MEMS H2 sensing chips with high consistency and optimized performance, which may also find broad applications in other MEMS chip technologies.

Realization of 1.54 μm electroluminescence via silicon-based erbium-doped SnO2 film devices

“…Near-infrared (NIR) EL has been attained in Er-doped metal oxides, including TiO 2 , ZnO, and Ga 2 O 3 [15][16][17]. As a novel multifunctional semiconductor with a direct bandgap of ∼3.9 eV [18], SnO 2 is extensively investigated in lightemitting devices (LEDs), solar cells, and sensors [19][20][21], which has not yet been reported on the rare-earth-doped EL device. Due to an appropriate bandgap, excellent optoelectronic properties, low maximum phonon energy [22], and high rare earth doping concentration [23], SnO 2 could be a suitable Er-doped material to realize the NIR EL.…”

Antenna Effect in Large Area Palladium-Coated Electrostatically Formed Silicon Nanowire for Ppb Level Hydrogen Sensing

“…Hydrogen gas (H 2 ) sensors for sub-ppm levels are vital for the early indication of leaks in various facilities of green energy, storage, chemical industry, nuclear reactors, etc. , For example, ppb level H 2 sensors are beneficial for early safety warnings and the elimination of thermal runaway in lithium-ion batteries, and they are also important for human breath-aided medical diagnosis, as the amount of H 2 concentration present in human breath is exceedingly low, below 1 ppm. Observing the presence of hydrogen at ppm levels can also function as an indirect measure for CO 2 , a crucial component in indoor ventilation. , This correlation arises from the fact that both CO 2 and H 2 are constituents of human exhalation.…”