Low-temperature and highly sensitive C2H2 sensor based on Au decorated ZnO/In2O3 belt-tooth shape nano-heterostructures

Gas sensors play a vital role on many aspects in our society, and have gained much progress, propelled by the development of nanoscience and nanotechnology. In this regard, metal oxides with heterojunctions have attracted tremendous attention owing to their enhanced gas sensing properties. Herein, belt-tooth shape ZnO/In2O3 nano-heterostructures has been achieved through a chemical vapor deposition process. The gas sensor fabricated from the as-prepared nano-heterostructures exhibits superior sensing performances for C2H2 gas at low operating temperature (90 degrees C). Moreover, the Au decorated ZnO/In2O3 nano-heterostructures (Au-ZnO/In2O3) exhibit enhanced C2H2 sensing properties such as higher response, less response time, better selectivity and smaller deviation from the ideal value of power exponent. More significantly, the response to C2H2 gas is maintained well in 30 days, indicating good long-term stability. In addition, both the potential-barrier-controlled carrier transport model combining with the surface depletion model and the unique properties of Au are presented to describe the C2H2 gas sensing mechanism of Au-ZnO/In2O3. This study offers an innovative methodology to design novel gas sensing materials and enhance gas sensing performances. (C) 2016 Elsevier B.V. All rights reserved.