Sensing of phosgene by a porous-like nanocrystalline diamond layer with buried metallic electrodes
Sensing of phosgene by a porous-like nanocrystalline diamond layer with buried metallic electrodes
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DOI：
10.1016/j.snb.2013.07.079
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发表时间：
2013-11-01
影响因子：
8.4
通讯作者：
Kromka, Alexander
中科院分区：
文献类型：
--
作者：
Davydova, Marina;Stuchlik, Martin;Kromka, Alexander
采用具有多孔结构的纳米金刚石作为半导体气敏元件的功能部件。该器件的功能是基于具有H端面的本征金刚石的二维p型表面电导率。金属电极埋在金刚石膜下面。因此，这些电极受到保护，免受有害物质的伤害，晶界促进了电子连接。在不同的工作温度下，用氧化性气体(光气、湿空气)检测了传感器结构的气敏特性。传感器在140℃下暴露在光气气体(20ppm)中后，表面电导率有明显的选择性增加两个数量级。密度泛函理论计算表明，光气分子与钻石之间没有直接的电荷转移。我们提出了一个模型，在该模型中，光气间接但有效地增加了H3O+的浓度，从而导致成倍的电子转移和显著的传感器响应。(C)2013爱思唯尔B.V.保留所有权利。
Nanocrystalline diamond with a porous-like morphology was used as the functional part of a semiconductor gas sensor. The device function is based on the two-dimensional p-type surface conductivity of intrinsic diamond with a H-terminated surface. Metallic electrodes are buried beneath the diamond film. Therefore, these electrodes are protected from harmful substances, and the electronic connection is facilitated by grain boundaries. The gas sensing properties of the sensor structure were examined using oxidising gases (i.e., phosgene, humid air) at various operating temperatures. A pronounced and selective increase by two orders of magnitude was found in the surface conductivity after sensor exposure to phosgene gas (20 ppm) at 140 degrees C. Density functional theory calculations indicated no direct charge transfer between the phosgene molecule and diamond. We present a model in which phosgene indirectly yet efficiently increases the H3O+ concentration, which consequently leads to multiplied electron transfer and a pronounced sensor response. (C) 2013 Elsevier B.V. All rights reserved.