气体传感器从其材料与结构来说是多种多样的,但简单而又实用的气敏元件多采用金属氧化物半导体作为原料,其中ZnO、SnO_2和γ—Fe_2O_3是常用的检测还原性气体的敏感材料。这三种金属氧化物是一种N型半导体,当其表面吸附了电子给予性气体分子(例如H_2、CO等气体)时,由于半导体与气体分子之间费米能级的差异,会使电子从吸附于表面的气体分子向半导体方向运动,因此N型半导体的载流子密度加大,导电率增 Gas sensors vary in material and structure, but simple and practical gas sensors mostly use metal oxide semiconductors as raw materials. Among them, ZnO, SnO 2 and γ-Fe 2 O 3 are commonly used to detect the sensitivity of reducing gases material. These three kinds of metal oxides are N-type semiconductors. When electron-donating gas molecules (such as H 2, CO and the like) are adsorbed on their surfaces, the difference in the Fermi level between the semiconductor and the gas molecules causes electrons Since the gas molecules adsorbed on the surface move in the direction of the semiconductor, the carrier density of the N-type semiconductor increases and the conductivity increases