ZnO and SnO2 one-dimensional sensors for detection of hazardous gases

There is need for reliable, low cost detectors to continuously monitor the air quality in presence of hazardous gases, harmful for human health. In this work we demonstrate how the use of different type of metal oxide one-dimensional sensors based on ZnO and SnO2 could provide high sensing capabilities together with differentiated responses to gases. The sensors can then be used together into a cost-effective portable sensor systems for quantitative detection of harmful emissions and contaminations. The gases tested in the present work are H-2 a highly explosive gas (4% is the lower explosion limit), H2S, one of the principal compounds involved in the natural cycle of sulphur in the environment, and DMMP, a simulant of the nerve agent Sarin. ZnO and SnO2 nanowires were prepared by Physical Vapour Deposition and ZnO polycrystalline nanorods were prepared by RF sputtering. The optimum response to low concentrations of DMMP at 500 degrees C was observed for ZnO materials, with respect to SnO2 at 500 degrees C. At 400 degrees C H-2 is better sensed by ZnO. Detection of H2S is better obtained with ZnO NRs compared to the other sensors.