Hydrogen sensing behaviour of platinum and palladium functionalized silicon nanowalls

In a chemi-resistive gas sensor, the sensing properties are essentially improved through surface functionalization. In the present work, silicon nanowalls (SiNWs) were carved on silicon wafers by metal-assisted chemical etching technique. Over the SiNWs, platinum (Pt) and palladium (Pd) nanoparticles were deposited through a fluoride-free galvanic displacement deposition technique. The surface-decorated SiNWs were then evaluated for their sensing behaviour towards hydrogen (H-2) gas. The morphological investigation revealed vertically aligned SiNW architecture with Pt and Pd nanoparticles sprinkled over the wall-tips. The crystallographic analysis indicated that the SiNWs has the original single-crystalline nature of the silicon wafer even after surface modification. Comparison of H-2 gas sensing efficacies indicates an similar to 8 and similar to 4-fold corresponding increase in Pd and Pt functionalized SiNWs, at 200 degrees C, with respect to pristine SiNWs. A plausible sensing mechanism is suggested with a suitable parallel resistance model. The combinatorial effect of single-crystalline SiNWs and catalytic properties of Pt and Pd resulted in enhanced sensing characteristics. Moreover, the economically scalable aptitude of the fabrication technique makes them suitable for real-time and facile industrial applications.

Automated summary

In this study, the sensing properties of a chemi-resistive gas sensor were improved by surface functionalization using silicon nanowalls (SiNWs) decorated with platinum (Pt) and palladium (Pd) nanoparticles. The morphological investigation revealed vertically aligned SiNW architecture with original single-crystalline nature even after surface modification. The combinatorial effect of single-crystalline SiNWs and catalytic properties of Pt and Pd resulted in enhanced sensing characteristics, making the fabrication technique economically scalable for real-time and facile industrial applications.