双层石墨烯在栅压调控下的各向异性刻蚀  

Anisotropic etching of bilayer graphene controlled by gate voltage

作　　者：王国乐 谢立[1] 陈鹏[1] 杨蓉[1] 时东霞[1] 张广宇[1,2,3,4] 

机构地区：[1]中国科学院物理研究所,北京凝聚态物理国家实验室,北京100190 [2]北京纳米材料与纳米器件重点实验室,北京100190 [3]量子物质科学协同创新中心,北京100190 [4]中国科学院大学物理学院,北京100190

出　　处：《物理学报》2016年第19期191-196,共6页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2013CB934500,2013CBA01602);国家自然科学基金(批准号:91223204,61325021,11574361,91323304);中国科学院B类先导项目(批准号:XDB07010100)资助的课题~~

摘　　要：石墨烯纳米结构在纳电子学研究领域表现出了良好的应用前景.氢等离子体各向异性刻蚀技术是加工石墨烯精细纳米结构的关键技术之一,可以实现10 nm以下平整的锯齿型石墨烯纳米带的可控加工.本文系统研究了外加电场对石墨烯各向异性刻蚀效应的影响,利用外加栅压实现了氧化硅衬底上的双层石墨烯各向异性刻蚀速率的调控.在±30 V栅压变化范围内,刻蚀速率比可达45.由此不仅可以提高大批量加工石墨烯纳米结构的效率,还可以实现5 nm以下极小尺寸石墨烯纳米带的可控加工.研究结果为石墨烯精细纳米结构器件的高效批量加工提供了思路.Graphene nanostructures are proposed as promising materials for nanoelectronics such as transistors, sensors, spin valves and photoelectric devices. Zigzag edge graphene nanostructures had attracted broad attention due to their unique electronic properties. Anisotropic hydrogen-plasma etching has been demonstrated as an efficient top-down fabrication technique for zigzag-edged graphene nanostructures with a sub-10 nm spacial resolution. This anisotropic etching works for monolayer, bilayer and multilayer graphene and the etching rate depends on substrate temperature with a maximum etching rate at arround 400？C. It has been also founded that the anisotropic etching is also affected by the surface roughness and charge impurities of the substrate. Atomically flat substrates with no charge impurities would be ideal for the anisotropic etching. So far the understanding of hydrogen-plasma anisotropic etching, e.g. whether hydrogen radicals or hydrogen ions dominate the etching process, remains unclear. In this work, we investigated the anisotropic etching of graphene under electrical field modulations. Bilayer graphene peeled off from grahpite on Si O2 substrate was used as the experimental object. 2 nm-Ti（adhesive layer） and 40 nm-Au electrodes was deposited by electronic beam evaporation for electrical contacts. Gate voltates were applied to the bilayer graphene samples to make them either positively or negitively charged. These charged samples were then subjected to the hydrogen anisotropic etching at 400？C under the plasma power of 60 W and gas pressure of 0.3 Torr. The etching rates were characterized by the sizes of the etched hexagonal holes. We found that the etching rate for bilayer graphene on Si O2 substrate depends strongly on the gate voltages applied. With gate voltages sweeping from the negative to the positive, etching rate shows obvious decrease.45 times of etching rate decrease was seen when sweeping the gate voltages from-30 V（positively charged） to 30 V（negatively charged）. This gate

关 键 词：石墨烯纳米结构 各向异性刻蚀 栅压 可控加工 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TN305.7[电子电信—物理电子学]