Hydrothermally treated sol solution of tin oxide for thin-film gas sensor

A sol solution containing SnO2 particles (crystallites) of 6 nm in average diameter was prepared by a hydrothermal treatment. The hydrothermal treatment was found to be very effective for suppressing the thermal growth of SnO2 grains. A thin-film sensor device, fabricated by spin-coating from the sol solution, consisted of SnO2 crystallites with 6 nm in mean diameter after calcination at 600°C. The device proved for better properties in sensitivity and response transient than a conventional sintered-block sensor device using SnO2 precipitated gel.