UV light-enhanced NO2 sensing by mesoporous In2O3: Interpretation of results by a new sensing model
UV light-enhanced NO2 sensing by mesoporous In2O3: Interpretation of results by a new sensing model
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DOI：
10.1016/j.snb.2013.02.025
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发表时间：
2013-10
影响因子：
8.4
通讯作者：
T. Wagner;C. Kohl;C. Malagù;N. Donato;M. Latino;G. Neri;M. Tiemann
中科院分区：
文献类型：
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作者：
T. Wagner;C. Kohl;C. Malagù;N. Donato;M. Latino;G. Neri;M. Tiemann
测量了介孔In2O3的光增强NO2传感行为，并通过一个新的传感模型对其进行了解释。该模型旨在解释（i）在紫外光照射下n型半导体In2O3的电子电阻的下降，（ii）光增强的氧化性气体反应，以及（iii）与非多孔材料相比，介孔In2O3中更快的反应和再生。与传统的双肖特基模型相反，电阻变化的主要因素是由于光还原而不是化学吸附导致的体相中氧空位施主态（导带以下0.18 eV）的变化。对于更快的反应和再生，我们提出了一个解释的基础上增强的氧扩散在In2O3晶格，特别是占主导地位的中孔结构。有序介孔In2O3对NO2的响应比非结构体材料（平均晶粒尺寸约为100 nm）更强。40 nm）。通过用UV光照射样品，反应显著加速。然而，介孔材料的响应是在照明的情况下较弱。
The light-enhanced NO2sensing behavior of mesoporous In2O3is measured and interpreted by means of a new sensing model. The model aims at explaining (i) the drop in electronic resistance of n-type semiconducting In2O3under UV light exposure, (ii) the light-enhanced reaction to oxidizing gases, and (iii) the faster reaction and regeneration in mesoporous In2O3as compared to non-porous material. Contrary to the conventional double Schottky model the dominating factor for the change in resistance is a change of oxygen vacancy donor states (0.18 eV below the conduction band) in the bulk phase due to photoreduction, instead of chemisorption. For the faster reaction and regeneration we propose an explanation based on enhanced oxygen diffusion in the In2O3crystal lattice, specifically dominant in the mesoporous structure. The response of ordered mesoporous In2O3to NO2is stronger than in case of unstructured bulk material (with an average grain size of ca. 40 nm). The reaction is significantly accelerated by illuminating the samples with UV light. However, the response of the mesoporous material is weaker in the illuminated case.