【作者】 张鹏；

【导师】 张彤；

【作者基本信息】 吉林大学 ， 集成电路工程（专业学位）， 2023， 硕士

【摘要】 金属氧化物半导体气体传感器是应用最广、研究最多的一类气体传感器。为了满足环境气体检测、人体呼出气体检测等应用需求,要求气体传感器的检出下限低至ppb量级,同时还要求传感器具有较高的灵敏度。金属氧化物结构微/纳米化是提高气体传感器灵敏度的一个有效策略,但同时会带来传感器初始电阻过高的问题,而高阻态的气敏材料会导致元件的功耗高、信号小、噪声大,不利于传感器信号采集和后续电路的设计。在n型金属氧化物半导体中掺杂较高价态的金属阳离子可以提高敏感层的载流子浓度,是降低气体传感器初始电阻的有效方法。基于此,本文以ZnO为基体材料,并向其中掺杂不同价态的阳离子。研究了不同掺杂方法和不同价态阳离子(Al³⁺、Sn⁴⁺和Sb⁵⁺和W⁶⁺)掺杂对传感器初始电阻、灵敏度、选择性、稳定性等的影响,分析了掺杂前后初始电阻和敏感特性变化的机理,主要研究内容如下:（1）研究了W⁶⁺掺杂在调控ZnO气体传感器电阻方面的作用。利用MOF牺牲模板法制备了不同含量W⁶⁺掺杂的ZnO材料。采取XRD、SEM等分析表征手段研究了ZnO掺杂不同含量的W⁶⁺后材料结构和形貌的变化。并对掺杂W⁶⁺前后的ZnO气体传感器的初始电阻值和气敏特性进行了测量,分析了W⁶⁺掺杂导致的传感器电阻和敏感特性变化的原因。（2）尽管在上一章的工作中利用W⁶⁺掺杂降低了ZnO电阻,但是这种以MOF为牺牲模板的掺杂方法并不利于材料的一致性、可控和大量制备。为此,在本章工作中,利用溶胶凝胶方法制备了Al³⁺、Sn⁴⁺和Sb⁵⁺掺杂的ZnO材料,使用SEM、XRD、XPS表征了材料结构、形貌、元素组成和化学态等性质。分析了不同阳离子掺杂后,材料内部的电学平衡状态、缺陷氧、吸附氧含量的变化,并研究了不同价态阳离子掺杂在调控ZnO基气体传感器电阻和敏感特性方面的作用。综上所述,本论文通过模板法和溶胶凝胶法分别制备了不同价态阳离子掺杂的ZnO基传感器,有效地降低了传感器的初始电阻。其中,通过溶胶凝胶法制备的Sn⁴⁺掺杂的ZnO材料在降低传感器电阻和提高传感器灵敏度等方面具有优势。本论文为低阻金属氧化物半导体传感器的构建提供了可行的思路和方法。更多还原

【Abstract】 The metal oxide semiconductor gas sensor is the most widely used and researched gas sensor.In order to meet the requirements of environmental gas detection and human exhaled gas detection,the detection limit of the gas sensor is required to be as low as ppb,and the sensor is also required to have high sensitivity.Micro/nano metal oxide structure is an effective strategy to improve the sensitivity of gas sensors,but it will also bring about the problem of high initial resistance,while high resistance gas sensitive materials will lead to high power consumption,low signal and high noise of components,which is not conducive to sensor signal acquisition and subsequent circuit design.Doping metal cations with higher valence states in metal oxide semiconductors can increase the carrier concentration of the sensitive layer,which is an effective method to reduce the initial resistance of gas sensors.Based on this,ZnO is used as the matrix material and doped with different valence cations.The effects of different doping methods and different valence cations(Al³⁺,Sn⁴⁺,Sb⁵⁺and W⁶⁺)doping on the initial resistance,sensitivity,selectivity and stability of the sensor are studied.The mechanism of the change of the initial resistance and sensitivity characteristics before and after doping is analyzed.The main research contents are as follows:（1）The role of W⁶⁺doping in regulating the resistance of ZnO gas sensors was studied.ZnO materials with different content of W⁶⁺doped were prepared using the MOF sacrificial template method.The changes in the structure and morphology of ZnO doped with different content of W⁶⁺were studied by XRD,SEM and other analysis and characterization methods.The initial resistance and gas sensing characteristics of ZnO gas sensors before and after W⁶⁺doping were measured,and the reasons for the changes in sensor resistance and sensing characteristics caused by W⁶⁺doping were analyzed.（2）Although the work in the previous chapter used W⁶⁺doping to reduce ZnO resistance,this doping method using MOF as a sacrificial template is not conducive to consistent,controllable,and large-scale preparation of materials.Therefore,in this chapter,Al³⁺,Sn⁴⁺and Sb⁵⁺doped ZnO materials were prepared by the sol gel method.The structure,morphology,element composition and chemical state of the materials were characterized by SEM,XRD and XPS.The changes in the electrical equilibrium state,defect oxygen,and adsorbed oxygen content within the material after doping with different cations were analyzed,and the effects of doping with different valence cations on regulating the resistance and sensitivity of ZnO based gas sensors were studied.In conclusion,ZnO based sensors doped with different valence cations were prepared by template method and sol gel method,which effectively reduced the initial resistance of the sensor.Among them,Sn⁴⁺doped ZnO materials prepared by the sol gel method have advantages in reducing sensor resistance and improving sensor sensitivity.This paper provides a feasible idea and method for the construction of low resistance metal oxide semiconductor sensors.更多还原