Enhanced He gas detection by V2O5-noble metal (Au, Ag, and Pd) nanocomposite with temperature dependent n- to p-type transition

Abstract

In this study, nanocomposite of V2O5 nanowires with noble metal (Au, Ag, and Pd) nanoparticles were fabricated by solution mixing and hydrothermal synthesis. These nanomaterials were analysed for their sensing properties towards Helium gas. Experiments carried out at room temperature conditions showed that V-Ag composite yielded the highest percentage response (73% at 150 ppm) and fast response/recovery times (8s/13 s at 100 ppm). The highest electrical conductivity of Ag nanoparticle was attributed as the principle reason behind the ultra-high response of V-Ag composite. The temperature dependent n- to p-type transition of the semiconducting material was also observed at higher sensing temperatures which was validated through Hall Effect measurements. The majority charge carrier transition from n- to p-type was observed near 47 °C. The highest response of V-Ag nanocomposite was recorded (108% at 5 ppm) at 100 °C when the material behaved like a p-type semiconductor.