Dip pen nanolithography-deposited zinc oxide nanorods on a CMOS MEMS platform for ethanol sensing
Dip pen nanolithography-deposited zinc oxide nanorods on a CMOS MEMS platform for ethanol sensing
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DOI：
10.1039/c5ra04584c
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发表时间：
2015-01-01
期刊：
影响因子：
3.9
通讯作者：
Guha, P. K.
中科院分区：
文献类型：
--
作者：
Santra, S.;De Luca, A.;Guha, P. K.
本文报道了一种新颖的氧化锌（ZnO）纳米棒的沉积使用浸笔纳米光刻（DPN）技术的SOI（绝缘体上硅）CMOS MEMS（微机电系统）微热板（MHP）和他们的特点作为一个低成本，低功耗的乙醇传感器。ZnO纳米棒是水热合成的，并沉积在MHP上，MHP包括嵌入在介电膜中的钨微加热器，在氧化物钝化层的顶部具有金叉指电极（IDE）。分别采用微加热器和IDE对传感层进行加热和电阻测量。由于SOI薄膜的存在，传感器器件具有极高的功率效率。发现MHP的电热效率为8.2摄氏度mW（-1），这导致在350摄氏度的操作温度下仅42.7mW功率。将具有ZnO纳米棒的CMOS MHP器件暴露于潮湿空气中的PPM水平的乙醇。对于乙醇浓度范围25-1000 ppm，传感器的灵敏度为5.8% ppm（-1）至0.39% ppm（-1）。ZnO纳米棒在350 ℃时显示出最佳响应。发现CMOS传感器具有湿度依赖性，这需要在现实世界的应用中加以考虑。在甲苯和丙酮存在下测试时，还发现传感器对乙醇具有选择性。我们相信，使用DPN光刻的ZnO纳米棒与CMOS MEMS衬底的集成提供了一种低成本、低功耗、智能的乙醇传感器，可以用于消费电子产品。
This paper reports on the novel deposition of zinc oxide (ZnO) nanorods using a dip pen nanolithographic (DPN) technique on SOI (silicon on insulator) CMOS MEMS (micro electro mechanical system) microhotplates (MHP) and their characterisation as a low-cost, low-power ethanol sensor. The ZnO nanorods were synthesized hydrothermally and deposited on the MHP that comprise a tungsten micro-heater embedded in a dielectric membrane with gold interdigitated electrodes (IDEs) on top of an oxide passivation layer. The micro-heater and IDEs were used to heat up the sensing layer and measure its resistance, respectively. The sensor device is extremely power efficient because of the thin SOI membrane. The electro-thermal efficiency of the MHP was found to be 8.2 degrees C mW(-1), which results in only 42.7 mW power at an operating temperature of 350 degrees C. The CMOS MHP devices with ZnO nanorods were exposed to PPM levels of ethanol in humid air. The sensitivity achieved from the sensor was found to be 5.8% ppm(-1) to 0.39% ppm(-1) for the ethanol concentration range 25-1000 ppm. The ZnO nanorods showed an optimum response at 350 degrees C. The CMOS sensor was found to have a humidity dependence that needs consideration in real-world application. The sensors were also found to be selective towards ethanol when tested in the presence of toluene and acetone. We believe that the integration of ZnO nanorods using DPN lithography with a CMOS MEMS substrate offers a low cost, low power, smart ethanol sensor that could be exploited in consumer electronics.