Mechanical and semi conductivity properties optimization of spin coated SnO2 based films for gas sensing applications

The development of solid-state chemical sensors, and more specifically gas sensors, is currently being carried out intensively since environmental pollution and security in the world and domestic ambient atmospheres represent acute problems with a high social impact.Synthesis and processing of films have a large influence on the mechanical properties of the sensing layers and on their electrical values. The broad option of sensor preparation makes it very difficult to compare results obtained by different processes. Inasmuch as formation of (i) mixture in atomic level, (ii) phase purity and (iii) porosity- surface area with desirable size and surface morphology, (iv) dopant materials and (v) mechanic integration of oxide thin films on substrate, are a significant issue about performance of devices, especially, in fabrication of multicomponent gas sensors. So, the selection of economic and effective production techniques is required. From this point of view, sol-gel technique includes several advantages such as production of well-defined oxides with excellent homogeneity and incorporation of dopant materials with extreme purity for fabrication of gas sensor components.The objective of this research contains the preparation, optimization of mechanical properties of semi conducting SnO2 based nanofilms on glass and silicon substrates from Sn-based solutions using sol?gel techniques and spin and dip methods in order to fabricate a stable gas sensor with high sensitivity and selectivity to several gases such as NOx, CO, CO2, H2S and LPG.