Al_(2)O_(3)를 첨가한 LaFeO_(3) 박막의 가스감지특성
Gas sensing characteristic of LaFeO_(3) thin films with Al_(2)O_(3) additives
가스감지 박막 LaFeo3 전자재료공학;
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Rare earth perovskite-type LaFeO_(3) thin films are promising candidates for use in gas sensors for environmental monitoring. They are p-type semiconducting oxides. LaFeO_(3) thin films and LaFeO_(3) thin films with 2 and 5 wt.% Al_(2)O_(3) additives were fabricated by r.f. magnetron sputtering method on Al_(2)O_(3) substrate with Pt electrodes. Their structural properties of thin films were examined by X-Ray diffraction and FESEM photographs. The compound of LaFeO_(3) and Al_(2)O_(3) was not found. The gas sensing characteristics of thin films with different heat treatments and Al-(2)O_(3) additives were examined. The sensitivities to NH_(3), CO, NO and C_(4)H_(8) gases were investigated with the thin films. The thin films showed high sensitivity to NH_(3) and CO gases. LaFeO_(3) thin-films annealed at 700℃ showed the sensitivities of about 70% to 200ppm NH_(3) gas at the working temperature of 350℃. LaFeO_(3)-Al_(2)O_(3)(2wt.%) thin films annealed at 800℃ showed the sensitivities of about 68% to 200ppm CO gas at the working temperature of 300℃. The time response for NH_(3) and CO gas was several tens seconds. The selectivity for NH_(3) and CO was observed.