In this research project we propose to conduct a study in order to understand the mechanisms of transport and solid-gas interactions that occur on the surface of SnO, Sn3O4 and SnO2 nanostructures, prepared in different devices. In order to obtain a better understanding of the phenomena involved, we chose to study individually and collectively (single and multiples), the nanobelts of each of the three compositions, wherein the first method allows discard extraneous interference, by analyzing only the intrinsic conduction mechanisms in nanostructures. For this, the materials will be synthesized by the carbothermal reduction method and will later be characterized by XRD, TEM and FE-SEM to confirm the effectiveness of the synthesis, a fundamental part for obtaining reliable results. The materials are also characterized with respect to its gas sensor response in the presence of oxidizing and reducing gases (e.g., NO2, CO, H2) at low concentrations (in the range of ppm), at working temperatures between 100 and 350 °C, and to achieve such temperatures will be used the conventional method of heating and the self-heating method, promising by not require external source to perform heating, generating energy savings and facilitating greater mobility in detecting leaks. The main new features of this work is the individual characterization of SnO and Sn3O4 nanobelts as gas sensor, the study of sensor response of nanobelts with same chemical composition but with different diameters (nanoscale), and the choice of the self-heating method for the gas sensor measurements, in the study of SnO and Sn3O4 structures. To perform these studies, it will be built individual devices using interdigitated electrodes in a dual-beam equipment (Focused Ion Beam - FIB) able to perform electronic lithography. Thus, the main contribution of this work to the literature is the study of solid-gas interactions in thermodynamically unstable material (SnO and Sn3O4), the study the influence of the analyte gas in the thickness of the depression layer (indirectly, the sensor properties) and the use of a new gas sensing method (self-heating) for these materials. Finally, it is expected that all this study lead to the development of sensor materials with high sensitivity, selectivity, fast response time and miniaturization capability, which is important aiming any future practical applications from these materials.
News published in Agência FAPESP Newsletter about the scholarship: