基于半导体纳米线的传感器研究

发布时间：2018-11-13 17:52

【摘要】：作为绿色能源,氢气在未来的新能源领域有着重要的应用前景。由于氢气无色无味,且爆炸限度很宽,因此在使用过程中必须对氢气浓度实现有效地监测。湿度传感器对日常生活和工业生产具有重要的意义。纳米材料独特的理化性质可以极大地提高传感器的性能,为新型传感器的研制提供了更多的思路。SiNWs和ZnO纳米线等材料不仅具有极大的比表面积,同时具有极高的表面活性,是敏感材料的理想选择。本文针对Pd/SiNWs/p-Si肖特基势垒二极管(SBD)氢气传感器和ZnO纳米线湿度传感器的制备展开研究。本文主要工作如下：第一,制备了Pd/SiNWs/p-Si SBD结构,并进行了SEM、XRD及EDS表征。采用湿法化学刻蚀的方法,制备了线径在40～80 nm的硅纳米线。XRD结果表明硅纳米线与衬底均为单晶结构。SiNWs顶端的无电镀Pd层厚度均匀,由许多Pd颗粒聚集在一起而形成的,呈多孔结构,是优异的气敏材料。第二,制备了Pd/SiNWs/p-Si SBD氢气传感器,通过I-V测试、I-t两种测试方法对氢气传感器的性能进行表征。研究了Pd层厚度和SiNWs的长度对氢气传感器响应的影响,发现SiNWs的刻蚀时间为50 min,Pd无电镀时间20 min条件下,传感器具有最好的响应。结果表明,所制备氢气传感器在常温下有很好的性能,很有潜力发展成为室温下工作的氢气传感器。基于化学吸附模型,对Pd/SiNWs/p-SiSBD氢气的化学特性敏感机理进行了研究与探讨。第三,通过对Pd/SiNWs/p-Si SB D的接触特性研究,揭示了氢气传感器的敏感机制。首先在Chueng模型基础上,通过数据拟合的方法,得到了SBD的电学特性参数。分析了理想因子、势垒高度和串联电阻等与温度的关系。分析了氢气的存在对SBD的电学特性参数的影响。第四,制备了ZnO纳米阵列湿度传感器。在MEMS技术加工的叉指电极上,通过溶胶凝胶法制备出了ZnO种子层,然后用化学水浴法制备出了ZnO纳米线阵列,制备了新型湿度传感器。测试结果表明所制备的湿度传感器可以工作于电容或者电阻模式,两者的响应时间约为1-2s。对于电容式传感器,电容响应湿滞为3.9%,低湿条件下为78.24 pF/%RH,高湿条件下灵敏度为420 pF/%RH；对于电阻式传感器,电阻响应的湿滞为9.1%；高湿条件下灵敏度为0.29 kΩ%RH,低湿条件下为3.11 kΩ/%RH。
[Abstract]:As a green energy, hydrogen has an important application prospect in the new energy field in the future. Since hydrogen is colorless and odorless, and the explosion limit is very wide, it is necessary to monitor the hydrogen concentration effectively. Humidity sensor is of great significance to daily life and industrial production. The unique physical and chemical properties of nanomaterials can greatly improve the performance of sensors and provide more ideas for the development of new sensors. Materials such as SiNWs and ZnO nanowires not only have a great specific surface area, but also have extremely high surface activity. It is an ideal choice for sensitive materials. The fabrication of Pd/SiNWs/p-Si Schottky barrier diode (SBD) hydrogen sensor and ZnO nanowire humidity sensor is studied in this paper. The main work of this paper is as follows: firstly, Pd/SiNWs/p-Si SBD structure was prepared and characterized by SEM,XRD and EDS. Silicon nanowires with wire diameter of 40 ~ 80 nm have been prepared by wet chemical etching. The XRD results show that both silicon nanowires and substrates are single crystal structures. The Pd layer without electroplating on the top of SiNWs is homogeneous in thickness and is formed by the aggregation of many Pd particles. Porous structure, is an excellent gas sensing material. Secondly, the Pd/SiNWs/p-Si SBD hydrogen sensor was prepared. The performance of the hydrogen sensor was characterized by I-V test and I-T test. The effects of the thickness of Pd layer and the length of SiNWs on the response of hydrogen sensor were studied. It was found that the best response was obtained when the etching time of SiNWs was 50 min,Pd and the electroplating time was 20 min. The results show that the hydrogen sensor has good performance at room temperature and has the potential to be used as a hydrogen sensor at room temperature. Based on the chemisorption model, the mechanism of chemical property sensitivity of Pd/SiNWs/p-SiSBD hydrogen was studied and discussed. Thirdly, the sensitive mechanism of hydrogen sensor is revealed by studying the contact characteristics of Pd/SiNWs/p-Si SB D. Firstly, based on the Chueng model, the electrical characteristic parameters of SBD are obtained by the method of data fitting. The relationship between ideal factor, barrier height and series resistance is analyzed. The influence of the presence of hydrogen on the electrical properties of SBD was analyzed. Fourthly, ZnO nanoscale humidity sensor was fabricated. The seed layer of ZnO was prepared by sol-gel method on the interDigital electrode fabricated by MEMS technology, and then the ZnO nanowire array was prepared by chemical water bath method, and a new humidity sensor was fabricated. The results show that the humidity sensor can work in capacitive or resistive mode, and the response time is about 1-2s. For capacitive sensor, the hysteretic hysteresis of capacitance response is 3.9, and the sensitivity is 420 pF/%RH; under low humidity condition and 78.24 pF/%RH, high humidity condition. For resistive sensor, the humidity hysteresis of resistance response is 9.1; The sensitivity is 0.29 k 惟% RH, under high humidity condition and 3.11 k 惟 /% RH. under low humidity condition.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TP212

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