Application of Transparent Conductive ITO Films Prepared by Electron Shower to Environmental Materials

ITO可作为液晶显示的透明导电膜，并可作为NO_2气体传感器，对环境造成污染。研究了用溅射和电子阵雨法制备的ITO薄膜的传感性能。当NO_2气体在测量管中稳定流动时，电子阵雨法制备的传感器膜的灵敏度优于溅射法制备的传感器膜。这是由于表面粗糙，这是由VLS（气液固）晶须沿着衬底生长获得的。一般来说，晶须垂直于衬底生长。然而，ITO晶须沿着衬底生长。我们找到了决定晶须生长方向的因子。研究了光催化可以降低隧道内NO_x的浓度。本研究采用电镀法制备的ZnO光催化剂对NO_x进行分解。采用价格低廉、操作简单的ito膜式气体传感器对NO_2气体分解过程进行了监测。当气体停止流动并在管内密封NO_2气体时，许多传感器显示NO_2浓度下降而没有泄漏，不能作为传感器使用。特别是当传感器温度较高或NO_2浓度较高时，这种现象更为明显。当重复测量时，未发生泄漏现象，可作为传感器使用。考虑了稳定和不稳定NO_2吸附位点的存在来解释这一现象。当传感器面积过小时，就会出现泄漏现象。当面积过大时，响应时间变长。结果表明，该传感器有一个合适的感应区域，对NO_2浓度有较高的响应

ITO is used as transparent conductive film for liquid crystal display, and it is possible to use as gas sensor for NO_2, which causes environmental pollution. The sensing properties of ITO films prepared by sputtering and electron shower method were investigated in this study. When NO_2 gas was flown steadily in a measurement tube, the sensitivity behavior of the sensor film prepared by the electron shower was more excellent than that prepared by sputtering. This was due to the rough surface, which was obtained by the growth of VLS (vapor-liquid-solid) whiskers along the substrate. In general, whiskers grew perpendicularly to the substrate. The ITO whiskers, however, grew along the substrate. We found the factor to determine the growth direction of the whiskers.It has been studied that the NO_x concentration in a tunnel was decreased by photocatalysis. In this study, NO_x was decomposed by ZnO photocatalyst prepared by electroplating. The low-priced and simple ITO-film gas sensor was used for the monitoring of the NO_2 gas decomposition. When the flow of the gas was stopped and NO_2 gas was sealed in the tube, many sensors showed the NO_2 concentration was decreased without leakage and they could not be used as a sensor. Especially, when the temperature of the sensor or the concentration of NO_2 was high, this phenomenon appeared remarkably. When the measurement was repeated, the leakage phenomenon did not occur, and it was used as sensor. This phenomenon was explained by the consideration of the existence of stable and unstable NO_2 adsorption sites. When the sensor area was too small, the leakage phenomenon appeared. When the area was too large, the response time became long. It was found that there was a proper sensor area to show a high response for a concentration of NO_2