Direct fabrication of SnO2-based thick film gas sensor using Micropen direct writing and laser microcladding

A direct-write technique for rapid prototyping and manufacturing of SnO2 thick film gas sensor has been presented in this paper. The technique combined Micropen direct writing, which deposited electronic pastes onto substrate according to the designed pattern, with laser microcladding to produce finer electrical components to overcome the resolution limitation of Micropen direct writing. With computer-aided design/computer-aided manufacturing (CAD/CAM), gas sensors with complicated patterns have been fabricated successfully by this technique without any mask. Nano-scale SnO2 paste without any doping element was used and irradiated by a continuous-wave laser with varied power. The effect of laser power on microstructure and gas-sensing properties of SnO2 thick film gas sensors has been investigated. The results indicate that the gas sensor fabricated by this hybrid technique exhibits excellent gas-sensing properties quite similar to those of screen-printed sensors.