Crack‐Free Periodic Porous Thin Films Assisted by Plasma Irradiation at Low Temperature and Their Enhanced Gas‐Sensing Performance

Abstract

Homogenous thin films are preferable for high-performance gas sensors because of their remarkable reproducibility and long-term stability. In this work, a low-temperature fabrication route is presented to prepare crack-free and homogenous metal oxide periodic porous thin films by oxygen plasma irradiation instead of high temperature annealing by using a sacrificial colloidal template. Rutile SnO2 is taken as an example to demonstrate the validity of this route. The crack-free and homogenous porous thin films are successfully synthesized on the substrates in situ with electrodes. The SnO2 porous thin film obtained by plasma irradiation is rich in surface OH groups and hence superhydrophilic. It exhibits a more homogenous structure and lower resistance than porous films generated by annealing. More importantly, such thin films display higher sensitivity, a lower detection threshold (100 ppb to acetone) and better durability than those that have been directly annealed, resulting in enhanced gas-sensing performance. The presented method could be applied to synthesize other metal oxide homogenous thin films and to fabricate gas-sensing devices with high performances.

In situ synthesis of porous array films on a filament induced micro-gap electrode pair and their use as resistance-type gas sensors with enhanced performances

“…[1][2][3] Since the first time with the advent of gas sensing element by Taguchi, 4 an enormous amount of efforts have been devoted to gas sensing materials in order to obtain high performances, such as fast response, 5, 6 high sensitivity, 7, 8 low power consumption, 9, 10 low detection limit, [11][12][13] preferable stability and good selectivity 14,15, . [29][30][31][32] However, besides the MOS sensing films with excellent performances such as high sensitivity to target gases, the structure of electrodes-equipped device substrate to support sensing films is another important factor to control gas performances, which affects the resistance of gas sensor to a large extent. In general, these nanostructured sensing films are fabricated on sensor substrates via drop-casting or brush coating.…”

Green synthesis of polysaccharide stabilized gold nanoparticles: chemo catalytic and room temperature operable vapor sensing application

“…28 Homogenous thin lms are preferable for highperformance gas sensors because of their remarkable reproducibility and long-term stability. 29 Low-temperature fabrication route to prepare crack-free and homogenous SnO 2 periodic porous thin lms by oxygen plasma irradiation has been reported and found to show response even at 100 ppb of acetone. 29 In the present study, green synthesis of AuNPs has been achieved using LBG as a reducing and stabilizing agent.…”

Micro/Nano Gas Sensors: A New Strategy Towards In-Situ Wafer-Level Fabrication of High-Performance Gas Sensing Chips

“…Firstly, a Si wafer (4 inch) covered by PS sphere colloidal monolayer template, with the sphere diameter of 500 nm, was integrally lifted off by aslant dipping into a 0.1 M SnCl 4 precursor solution in a beaker due to surface tension of the solution and then floated on the solution surface. In succession, the floating PS colloidal monolayer was picked up with the MHP wafer (4 inch) and dried at 120 °C for 0.5 h. At this stage, owing to the strong hydrolysis of Sn 4+, 63, there must undergo the hydrolysis reaction and it mainly produces Sn(OH) 4 (or H 2 SnO 3 •H 2 O). After it was subsequently heated at 400 °C for 2 h, the PS template was burned away, a wafer-scaled ordered porous SnO 2 thin film was formed on the MHP wafer, and thus a great many MHP-NPA integrated sensors are simultaneously fabricated and arranged on the wafer.…”