Controllable synthesis and crystal facet, composition and temperature dependent gas sensing properties of Sn1−xS-CdS superlattice nanowires with ultrafast response

Abstract

Sn1−xS-CdS superlattice nanowires (NWs) with fast response and good selectivity in low-temperature operating environments for potential applications as gas sensing materials, were designed rationally and synthesized controllably. This work investigated in detail the dual selective gas sensing performance of Sn1−xS-CdS superlattice nanowires that crystal facets change with the tunable composition. The results demonstrated that the Sn0.38S-CdS superlattice NWs with the structure of (0 0 4) lattice plane of SnS growing epitaxially along the [0 0 2] crystallization direction of CdS. And the gas sensors based on Sn0.38S-CdS superlattice NWs displayed the best gas sensing properties, including ultrafast response to acetone with 1 s at 290 °C, and good selectivity to H2S with selectivity value of 29886% at 190 °C. The gas sensing mechanism was carefully investigated by the chemical stability of gas molecules and the adsorption energy on the different crystal planes, as well as the energy band structure of the heterostructure. The study highlights an efficient rout to the development of high-performance multi-functional gas sensors.