【作者】 孙佳；

【导师】 万青；

【作者基本信息】 湖南大学 ， 凝聚态物理， 2009， 硕士

【摘要】 纳米材料由于具有体相材料所不具备的新奇的物理与化学性质引起了人们广泛的研究和关注。本文报道采用基于气-液-固（Vapor-Liquid-Solid）生长机理的气相输运法制备单晶SnO₂纳米线,结合原位调控掺杂思想,制备了Sb掺杂SnO₂纳米线。用高分辨率透射透射电子显微镜进行结构表征发现SnO₂纳米线有很好的单晶性。研究发现SnO₂纳米线的电学特性通过掺杂能够得到很好的调控。纯SnO₂纳米线与Ti/Au电极之间表现出明显的肖特基接触,适合用作紫外光探测;轻掺杂的SnO₂纳米线适合用于晶体管的沟道,器件表现出优越的晶体管特性;重掺杂的SnO₂纳米线是一种良好的透明导体。本论文发展金丝掩模法制备Sb轻掺杂的SnO₂纳米线场效应晶体管。在没有热退火和表面修饰的前提下,纳米线的表面损伤能够很好的避免,这种方法适合于一维无机纳米材料的电学以及光电子学的研究。电学测量表明制备的晶体管具有高性能n型晶体管特性,在转移曲线中没有回滞现象。单根纳米线晶体管的开关比为106,亚阈值斜率为240mV/decade,迁移率为12.4cm²/Vs。与传统的一维纳米材料场效应晶体管制备技术相比有如下优点:a.简单。不需要任何光刻工具,所需设备和操作过程相对传统微纳加工技术简单。b.有效。电极制备过程中没有辐射损伤和有机污染（电子束曝光和光刻都要用光刻胶,聚焦离子束存在有机污染）,也没有物理接触,有利于获得高性能器件。c.选择性好。制备过程中可以先选择感兴趣的纳米线,然后在感兴趣的纳米线的合适区域制备器件。d.灵活。制备器件的构型（如对称电极结构或非对称电极结构）和沟道长度可调。与传统的硅基薄膜晶体管相比,纳米线薄膜晶体管的主要优点在于器件制作过程与半导体沟道材料生长过程的分离,不需要考虑器件的衬底承受温度而获得单晶沟道材料。本论文利用金丝掩模法制备了Sb轻掺杂的SnO₂纳米线薄膜晶体管,该器件表现出较好的晶体管特性,开关比达到10⁵,亚阈值摆幅为2.3V/decade。更多还原

【Abstract】 Nano-materials have gained a tremendous amount of attention due to their novel physical and chemical properties which are different from their corresponding bulk materials. The thesis reports fabrication of undoped SnO₂ nanowire and in-situ doping of Sb element into SnO₂ nanowires via Chemical Vapor Deposition （CVD） method with Vapor-Liquid-Solid （VLS） technique. High Resolution Transimission Electron Microscopy （HRTEM） was applied to characterize the structure of one-dimensional SnO₂ nanostructures, and good crystallinity was proved by HRTEM. The electrical characteristics of SnO₂ nanowires can be reasonable controlled through doping. The undoped SnO₂ nanowires show Schottky contact to Ti/Au electrodes in air and are suitable for the detection of UV light. Lightly Sb-doped nanowires are promising as high-performance nanowires transistors, and degenerately Sb-doped SnO₂ nanowires are transparent metallic conductors.A gold microwire mask method is developed for the fabrication of transistors （FETs） based on single lightly Sb-doped SnO₂ nanowires. Damage and disadvantage touch of the nanowire’s surface can be avoided without any thermal annealing and surface modification, which is very convenient for the fundamental electrical and photoelectric characterization of one-dimensional inorganic nanomaterials. Transport measurements of the individual SnO₂ nanowire device demonstrate the high-performance n-type field effect transistor characteristics without significant hysteresis in the transfer curves. The current on/off ratio and the subthreshold swing of the nanowire transistors are found to be 106 and 240mV/decade, respectively. Compared to traditional 1D inorganic nanomaterials FETs fabrication techniques, the advantages of our fabrication method have been listed as follows: a) No lithographic tools are used, it is very appropriate to fundamental research because the entire process of fabrication method is very simple and little equipment is needed. b) In the process of the electrode deposition without radiation damage, which benefit to improve the device performance. c) Any nanowire can be flexibly selected and used for fabricating functional devices in specific area which we are interested in. d) The configuration of the nanodevice （such as symmetrical or asymmetrical source/drain electrodes） and the length of active channels can be effectively adjusted.The key advantage of the nanowires thin film transistors （TFTs） approach compared to conventional TFT techniques is the clear separation of the device fabrication stage from the material growth stage, such that there is no longer need to be concerned with compatibility with the device substrate during growth, and high growth temperature can be used to obtain crystalline materials. The gold microwire mask method was also employed for the fabrication of SnO₂ nanowires TFT, this device shows high-performance, the current on/off ratio and subthreshold are found to be 10⁵, and 2.3V/decade.更多还原