Seol-Gel법에 의한 CO 감지용 SnO₂센서 특성 = Characteristics on Sensitivity of SnO₂CO gas sensor by Sol-Gel Methods

다국어 초록 (Multilingual Abstract)

Ultra-fine particles of SnO₂was synthersized by the sol-gel powder processing using tin(Ⅱ) chloride dihydrate(SnCl₂·2H₂O) and ethanol(C₂H_(5)OH) as raw materials. Gel powders can be obtained by drying of sol at 120℃ after aging 72hrs and 168hrs. The amount of SnO₂phase was increased with temperature because of the evaporation of volatile components, and the creation of SnO₂phase was almost done by the heat treatment at 700℃/30min. The grain sizes after firing are about 20-30nm, and it showed the narrow distribution of grain size. The specimens to measure electrical properties were fabricated by the thick film screen printing technique on the alumina substrates. The conductance of SnO₂was increased with temperature up to 380℃ by the typical conduction mechanism of semiconducting ceramics. There was a region of constant conductance between about 200℃ and 380℃ due to the increment of electron concentration with temperature and the annihilation of conduction carriers by the absorption and electron trapped-ionization of oxygen on the surface of SnO₂, It was finally showed the intrinsic behaviors above 450℃. The sensing properties of response time, recovery, and sensitivity of CO were improved with aging time.