Ghosh Sugato, Roychaudhuri Chirasree, Bhattacharya Raghunath, Saha Hiranmay, Mukherjee Nillohit
Centre of Excellence for Green Energy and Sensor Systems, Bengal Engineering and Science University , Howrah 711103, West Bengal, India.
ACS Appl Mater Interfaces. 2014 Mar 26;6(6):3879-87. doi: 10.1021/am404883x. Epub 2014 Mar 5.
Metal oxide semiconductors (MOS) are well known as reducing gas sensors. However, their selectivity and operating temperature have major limitations. Most of them show cross sensitivity and the operating temperatures are also relatively higher than the value reported here. To resolve these problems, here, we report the use of palladium-silver (70-30%) activated ZnO thin films as a highly selective methane sensor at low operating temperature (∼100 °C). Porous ZnO thin films were deposited on fluorine-doped tin oxide (FTO)-coated glass substrates by galvanic technique. X-ray diffraction showed polycrystalline nature of the films, whereas the morphological analyses (field emission scanning electron microscopy) showed flake like growth of the grains mainly on xy plane with high surface roughness (107 nm). Pd-Ag (70-30%) alloy was deposited on such ZnO films by e-beam evaporation technique with three different patterns, namely, random dots, ultrathin (∼1 nm) layer and thin (∼5 nm) layer as the activation layer. ZnO films with Pd-Ag dotted pattern were found show high selectivity towards methane (with respect to H2S and CO) and sensitivity (∼80%) at a comparatively low operating temperature of about 100°C. This type of sensor was found to have higher methane selectivity in comparison to other commercially available reducing gas sensor.
金属氧化物半导体（MOS）作为还原性气体传感器广为人知。然而，它们的选择性和工作温度存在重大局限性。大多数此类传感器表现出交叉敏感性，并且工作温度也相对高于此处报道的值。为了解决这些问题，在此我们报告使用钯 - 银（70 - 30%）活化的氧化锌薄膜作为在低工作温度（约100°C）下具有高选择性的甲烷传感器。通过电沉积技术将多孔氧化锌薄膜沉积在氟掺杂氧化锡（FTO）涂层的玻璃基板上。X射线衍射表明薄膜具有多晶性质，而形态分析（场发射扫描电子显微镜）显示晶粒主要在xy平面上呈片状生长，表面粗糙度较高（107纳米）。通过电子束蒸发技术以三种不同图案，即随机点、超薄（约1纳米）层和薄（约5纳米）层作为活化层，将钯 - 银（70 - 30%）合金沉积在这种氧化锌薄膜上。发现具有钯 - 银点状图案的氧化锌薄膜在约100°C的相对较低工作温度下对甲烷（相对于硫化氢和一氧化碳）具有高选择性和灵敏度（约80%）。与其他市售的还原性气体传感器相比，这种类型的传感器具有更高的甲烷选择性。
