금속산화물을 첨가한 Co3O4 후막의 가스 감지특성

Abstract

Co3O4 and Co3O4-based thick films with additives such as Co3O4-Fe2O3(5 wt.%), Co3O4-SnO2 (5 wt.%), Co3O4-WO3(5 wt.%) and Co3O4-ZnO(5 wt.%) were fabricated by screen printing method on alumina substrates. Their structural properties were examined by XRD and SEM. The sensitivities to iso-C4H10, CH4, CO, NH3 and NO gases were investigated with the thick films heat treated at 400℃, 500℃ and 600℃. From the gas sensing properties of the films, the films showed p-type semiconductor behaviors. Co3O4-SnO2(5 wt.%) thick film heat treated at 600℃ showed higher sensitivity to i-C4H10 and CO gases than other thick-films. Co3O4-SnO2(5 wt.%) thick film heat treated at 600℃ showed the sensitivity of 170 % to 3000 ppm iso-C4H10 gas and 100 % to 100 ppm CO gas at the working temperature of 250℃. The response time to i-C4H10 and CO gases showed rise time of about 10 seconds and fall time of about 3~4 minutes. The selectivity to i-C4H10 and CO gases was enhanced in the Co3O4-SnO2(5 wt.%) thick film.