气敏金属氧化物半导体纳米球壳的制备和电输运调控

Gas sensors based on metal oxide semiconductor, are now employed for detection of toxic and inflammable gases and monitoring atmospheric gases. In order to expande scale and scope of use, gas sensors with better gas properties at room temperature should be designed and prepared. Considering that the tremendous interface area of nanostructures indicate the potential for high performance of material, a nanoshell with some nanopores was proposed and designed according to the working principle of the gas sensor. The properities of electronic transport and gas sensitivity of a individual nanoshell could be controlled by controlling the characterization of micro structure and the interfaces of the nano material. However, the electronic transport of the gas sensor composed of much nanostructure has a low transport efficiency, which is caused by the loss of electricity from itself. In response to the bottleneck problems, a solution of mixing nanoparticles of noble metal and nanoshell of metal oxide was gave, which base on the theory of percolation.Then, the invalid resistance of electricity and the loss of electricity could decrease. Meanwhile the transport efficiency of electron and gas sensitivity could increase. So, It is probable that the nano sensor with high sensitivity at room temperature could be prepared.

本项目针对气敏传感技术在生产生活实践中的巨大应用，依据气敏传感原理和纳米材料的属性，从提高传感器性能出发，设计出一种提高气敏灵敏度（GS）的结构——带有纳米孔隙的纳米球壳。拟通过对微结构、界面的调控来实现对单个纳米结构本征微观的电输运调控，从而实现GS的提高。同时，依据逾渗原理，提出MOS和贵金属纳米颗粒复合的机制，以实现对宏观元件（由纳米结构集合体组成）的电输运调控，从而解决宏观元件存在的电输运瓶颈问题即电输运效率低、电流损失大。通过增加电流通道，减小无效电阻和电流损失，来提高器件的电输运效率和气敏灵敏度，最终达到制备出常温使用的高GS纳米气敏传感器的目的。

气敏传感技术在生产生活实践中具有重大的应用价值。我们采用碳球为模板的方法，合成了具有介孔结构的纳米金属氧化物球壳（Fe2O3，ZnO）。首先，通过控制水热反应的温度，实现了对碳球模板和球壳尺寸的调控。再次，通过控制Fe3+的浓度，实现了对球壳的介孔尺寸分布，团聚程度、比表面积和表面活性位点多少的调控；制备了纳米ZnO-SnO2纳米异质结空心球壳，系统研究了它的气敏性能；通过控制HAuCl4的浓度，依据贵金属Au在ZnO纳米球壳上异质成核和生长的原理，实现了Au含量的调控；通过还原性气体H2和氧化性气体O2的退火，实现了对表面组分和表面能的调控；通过以上技术手段实现了对气敏性能的调控。总之，本项目系统研究了比表面积、表面能、表面组分和Au含量对载流子输运和气敏性能的影响。本项目研究不仅为深刻理解气敏原理和设计更高性能的气敏原型器件指明了方向；而且为我们开辟了一个长期稳定的研究方向。