CO2 gas sensor based on silicon nanowires modified with metal nanoparticles

Silicon nanowire arrays (SiNWs) prepared by a one-step metal-assisted electroless etching method in HF/AgNO3 aqueous solution were used to fabricate CO2 gas sensor. SiNWs were modified by nanoparticles of Pt and Au by simple immersion in HF aqueous solutions containing platinum and gold salts, respectively. Morphology of SiNWs was investigated using scanning electron microscopy (SEM). Chemical analysis was performed by energy dispersive X-ray (EDX). The structures manufactured to sensing the CO2 gas were of type Metal/SiNWs/p-Si/Al. The electrical characterization (I–V) was performed in primary vacuum and CO2 at different concentrations. It was found that the modification metal type strongly influences the I–V characteristics. Finally, the sensing characteristics and performance of the sensors were investigated.