石墨烯-六方氮化硼面内异质结构的扫描隧道显微学研究  

Scanning tunneling microscopy study of in-plane graphene-hexagonal boron nitride heterostructures

作　　者：刘梦溪[1] 张艳锋[1,2] 刘忠范[1] 

机构地区：[1]北京大学化学与分子工程学院,北京大学纳米化学研究中心,北京100871 [2]北京大学工学院材料科学与工程系,北京100871

出　　处：《物理学报》2015年第7期60-70,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51222201;51290272;11304053;51121091);国家科技支撑计划(批准号:2011CB921903;2012CB921404;2012CB933404;2011CB93300;2013CB932603)资助的课题~~

摘　　要：石墨烯-六方氮化硼面内异质结构因可调控石墨烯的能带结构而受到广泛关注.本文介绍了在超高真空体系内,利用两步生长法在两类对石墨烯分别有强和弱电子掺杂的基底,即Rh(111)和Ir(111)上制备石墨烯-六方氮化硼单原子层异质结构.通过扫描隧道显微镜及扫描隧道谱对这两种材料的形貌和电子结构进行研究发现:石墨烯和六方氮化硼倾向于拼接生长形成单层的异质结构,而非形成各自分立的畴区;在拼接边界处,石墨烯和六方氮化硼原子结构连续无缺陷;拼接边界多为锯齿形型,该实验结果与密度泛函理论计算结果相符合;拼接界面处的石墨烯和六方氮化硼分别具有各自本征的电子结构,六方氮化硼对石墨烯未产生电子掺杂效应.In-plane heterostructure of hexagonal boron nitride and graphene（h-BN-G） has become a research focus of graphene due to its predicted fascinating properties such as bandgap opening and magnetism, which hence has ignited the attempt of experimentally growing such in-plane two-dimensional（2D） hybrid materials. Many previous researches demonstrated the synthesis of such heterostructures on Cu foils via chemical vapor deposition（CVD） process. The obtained 2D hybrid materials would offer a possibility for fabricating atomically thin electronic devices. However, many fundamental issues are still unclear, including the in-plane atomic continuity, the edge type, and the electronic properties at the boundary of hybridized h-BN and graphene domain. To clarify these issues, we report the syntheses of h-BN-G monolayer heterostructures on strongly coupled Rh（111） substrate and weakly coupled Ir（111） substrate via a two-step growth process in an ultrahigh vacuum（UHV） system, respectively. With the aid of scanning tunneling microscopy（STM）, it is revealed that graphene and h-BN could be linked together seamlessly on an atomic scale at the linking boundaries. More importantly, we find that the atomically sharp zigzag-type boundaries dominate the patching interface between graphene and h-BN as demonstrated by atomic-scale STM images. To understand the physical origin of the atomic linking of the hBN-G heterostructures, we also perform density functional theory（DFT） calculations, including geometry optimizations and binding energy calculations for different kinds of linking interfaces. The calculated results reconfirm that graphene prefers to grow on the h-BN domain edges and form zigzag linking boundaries. Besides the atomic structures on the linking interfaces, the electronic characteristics are also of particular importance. It is worth noting that the substrates coupled strongly with graphene by π-d orbital hybridization（such as Rh（111） and Ru（0001））, lead to downward shift of graph

关 键 词：石墨烯 六方氮化硼 面内异质结构 扫描隧道显微镜 

分 类 号：O611.2[理学—无机化学] TH742[理学—化学]