Exploration of the use of p-TeO2-branch/n-SnO2 core nanowires nanocomposites for gas sensing

Abstract

Abstract Branched nanowires (NWs) are a novel class of composite materials with increased surface area relative to their pristine one-dimensional counterparts. Accordingly, they are good choice for gas sensing studies. In this study, p-n, TeO2-branched SnO2 NWs were produced by a two-step catalyst-assisted vapor-liquid-solid (VLS) growth technique for gas sensing studies. First, SnO2 NWs were synthesized from highly pure Sn powders, and TeO2 branches were subsequently added. The fabricated samples were well characterized in terms of morphology, crystallinity, and chemical composition. Gas sensing results exhibited the enhanced NO2 sensing capability of TeO2 branched SnO2 NW sensors relative to pristine SnO2 NWs. In particular, the maximum responses (Rg/Ra) of pristine and TeO2 branched SnO2 sensors to 10\u202fppm NO2 were 6.34 and 10.25, respectively. Furthermore, dynamics of TeO2 branched sensor at the optimal temperature was faster. Superior sensing properties of TeO2 branched SnO2 NWs were related to the high surface area of the branched sensors and creation of p-n heterojunctions on the surfaces of this sensor. We believe that branching is a good way to realize gas sensors for practical usages.