Performance Of SnO₂ Nanoparticle-Embedded Thin Film Gas Sensor Based On Textured Substrate

Nowadays, detection of ethanol and methane gas has been concerned by more and more researchers around the world. In numerous materials, properties of Sn O2 nanoparticles materials are better than traditional materials. So nanoparticle-embedded thin film gas sensors become one of the hot research topics. The textured substrate structures have great specific surface area, and there are a lot of surface defects and high activation energy. Based on the above advantages, this dissertation focuses on the investigation of Sn O2 nanoparticle-embedded thin film gas sensor based on textured substrate and the detection for ethanol and methane gas. The specific contents are as follows.(1) Interdigital electrodes of titanium were deposited on the silicon or glass substrate using electron beam evaporation. Sn O2 nanoparticle-embedded thin films could be deposited on the substrate with magnetron sputtering. The size of nanoparticles were around 16 nm when the growth rate was 3nm/min the oxygen partial was 20%, power and pressure was 70 W and 0.5Pa and target base was 6.5cm.(2) The textured silicon substrate was prepared according to the anisotropic etching principle. Specific surface area and defects have been enhanced by employing the textured substrates. For the detection of ethanol gas, the sensor response time and other performances have been improved effectively. The response time and recovery time were 3 s and 8 s, respectively.(3) The Pd Cl2 and Fe Cl3 solution were coated on Sn O2 thin film. With different rapid thermal annealing temperature(250 ℃~ 550 ℃), the sample exhibited the highest response values when the annealing temperature was 350 ℃. When doped with Pd, Pd metal can serve as catalyst during annealing treatment, which reduced the size of Sn O2 nanoparticles from 16 nm to 8nm. Meanwhile, the selectivity to methane gas was improved, and the response value has been improved above three times.