低维碳材料的热电子发射及其在真空电子学的应用  

Thermionic Emission of Low-Dimensional Carbon Materials and Its Applications in Vacuum Electronics

作　　者：李志伟 吴功涛 王雨薇 魏贤龙[1] LI Zhi-wei;WU Gong-tao;WANG Yu-wei;WEI Xian-long(Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics,Peking University,Beijing 100871,China)

机构地区：[1]北京大学电子学系纳米器件物理与化学教育部重点实验室,北京100871

出　　处：《真空电子技术》2018年第3期6-12,57,共8页Vacuum Electronics

基　　金：国家自然科学基金项目(61371001);国家重点基础研究发展计划项目(2013CB933604)

摘　　要：真空电子器件的微型化是真空电子学的一个重要发展趋势。随着微纳加工技术的发展和新材料的发现与应用,纳米尺度真空沟道三极管取得了一定的进展。当前实现真空三极管微型化的主要手段还是基于场发射的阴极,而场发射对发射部位原子结构的强依赖决定了在集成时不可避免遇到均一性和稳定性差的问题。我们发现了碳纳米管和石墨烯具有不同于传统热电子发射的热发射新机制,基于半导体微加工技术,利用石墨烯和碳纳米管作为电子发射材料,实现了热阴极的微型化、片上化和阵列化,并进一步利用石墨烯微型热阴极实现了一种新结构的石墨烯真空三极管。石墨烯微型热阴极具有工作电压低(2~4V)、响应时间短(<1μs)、发射电流可大幅度调制、可控性好等特点。石墨烯真空三极管的开关比高达106,亚阈值斜率仅为120mV/dec,工作电压不足10V,与石墨烯固态三极管相当。我们还演示了石墨烯真空三极管的片上集成,将两个单极性石墨烯真空三极管集成在一起实现了双极性的真空电子器件。由于石墨烯真空三极管具有开关性能好、工作电压低、可集成等特点,未来有望基于石墨烯真空三极管实现更复杂的器件和真空集成电路。The miniaturization of vacuum electronic devices is an important trend in the field of vacuum electronics. With the development of micro-nanofabrication technologies and the discovery of new materials, especially nanomaterials, there has been some progress in nanoscale vacuum channel transistors. The common way to realize the miniaturization of vacuum transistor is field emission, which always has a poor uniformity and stability as field emission highly relies on the atomic structure of the emission position. A new thermionic emission mechanism for nanomaterials was proposed and an array of on-chip micro thermionic emitter was fabricated with micro-nanofabrication technologies using graphene and carbon nanotubes as emission materials. The graphene-based micro thermionic emitter was characterized by low operating voltage（2~4 V）, short response time（〈1 μs） and highly controllable emission current. A new vacuum transistor based on the graphene-based micro thermionic emitter was fabricated which had an operating voltage of less than 10 V, an on/off ratio of over 10 6 and a subthreshold slope of 120 mV/dec. An integration of graphene-based vacuum transistors was demonstrated with two single transistors to realize a bipolar vacuum device. Graphene-based vacuum transistors which are based on the thermionic emission of low-dimensional materials are promising to realize complex devices and vacuum integration circuits.

关 键 词：微型真空电子三极管 碳纳米管 石墨烯 微型热阴极 石墨烯真空三极管 

分 类 号：TN32[电子电信—物理电子学]