Porous silicon filled with Pd/WO3-ZnO composite thin film for enhanced H2 gas-sensing performance

Abstract

Here, pure ZnO, WO3 and Pd/WO3-ZnO composite porous thin films were successfully synthesized directly on porous silicon by a reactive DC magnetron sputtering technique. A sensor based on the Pd/WO3-ZnO composite porous thin films showed remarkably improved H2 sensing performance with good stability and excellent selectivity compared to that of pure WO3 and ZnO, at a relatively lower operating temperature (200 °C) and with a low detection range of 10-1000 ppm. The enhanced response can be attributed to the heterojunction formed between two dissimilar materials. The underlying mechanism behind their good performance for H2 gas was discussed in detail.