Efficient bimetallic nanoparticles embedded-porous silicon CO gas sensor

摘要

In this study, the surface modification process involving the embedding of Au or Pd monometallic and Au-Pd bimetallic alloy nanoparticles within porous silicon-based gas sensor was investigated. Porous silicon layer (P-si) was prepared by photo electrochemical etching (PECE) by using 635 nm diode laser of 25 mW/cm(2) intensity. AuNPs/P-si, PdNPs/P-si and Au-PdNPs/P-si hetero structures were prepared by ion reduction process. This was materialized dipping fresh P-si in a salt solution containing HAuCl4 and PdCl2; mixed at ratio 1:1 for about (1.2, 5 and 2 min), respectively. The heterostructures were investigated by utilizing scanning electron microscopy (SEM), FTIR analysis, X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDS). Efficient gas sensing process was recorded for modified porous silicon (P-si) gas sensor with smallest bimetallic Au-Pd nanoparticles size. Considerable improvements were noticed in sensitivity and temporal response after incorporating the bimetallic Au-Pd nanoparticles into the silicon matrix as compared to bare P-si and monometallic nanoparticles gas sensors due to the high specific surface area and the higher value of the barrier height of Au-PdNPs/P-si hetero structures.