Enhanced nitrogen dioxide sensing properties of Ni4Cr1/SnO2 heterostructures

摘要

Highly sensitive nitrogen dioxide (NO2) gas sensors were prepared based on NiCr/SnO2 heterostructures of conducing films. NiCr/SnO2 heterostructures were developed by DC sputtering of NiCr target followed by RF sputtering of SnO2. Annealing of heterostructures at 600 degrees C leads to high crystallinity as well as good adhesion to the substrate. The sensor platform is based on planar interdigitated electrodes. The surface morphology and structural properties of NiCr/SnO2 heterostructures were examined by field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The NO2 gas sensing properties were studied at different operation temperatures (25-250 degrees C) and gas concentrations (5-100 ppm). The results exhibit a sensing response of 6.9 for 100 ppm NO2 with fast recovery times similar to 5s, and 7s, respectively. The synergetic effects induced by the NiCr-decoration including enhanced response and lowered operation temperature were observed. The sensing mechanism of the NiCr/SnO2 heterostructures sensor was also discussed in detail. It is reported that as-prepared sensors based on NiCr/SnO2 heterostructures display a phenomenal option for utilizing in the field of a gas sensor for attaining very high 3-S parameters (sensor response, selectivity, and stability).