ZnO/γ-Fe2O3 Charge Transfer Interface toward Highly Selective H2S Sensing at a Low Operating Temperature of 30 °C

ZnO/gamma-Fe2O3 heterostructure has been deposited in the form of thin films using a single step facile electrochemical technique. Considering the unique properties of both ZnO and gamma-Fe2O3 toward the sensing of reducing gases, the concept of forming a heterostructure between them has been conceived. The structural characterization of the deposited material has been performed using X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy, which revealed a flowerlike morphology with the coexistence of both ZnO and gamma-Fe2O3 leading to the formation of a heterostructure. The material showed excellent sensing properties toward the selective detection of H2S at room temperature (30 degrees C) among the three test gases, namely, CH4, H2S, and CO. The effect of relative humidity was also studied to have an idea about the performance of the device under a real situation. The results are promising and better than those of many commercially available sensors. The room temperature selective detection will help in facile fabrication of portable gadgets.