石墨烯/六角氮化硼复合薄膜材料的制备、表征与生长机理研究

Graphene and hexagonal boron nitride (h-BN) have both drawn great attention due to their special properties and wide-range potential applications. Especially, the combination of the two materials arises more possibilities for application and experimentation. Although there are many methods for the syntheses of graphene, the production of h-BN is still confined in a laboratory level. Currently, the composite material of graphene and h-BN is achieved by simply transferring one of the films onto another, by which defects can be greatly introduced. The applicant has perfected a technique called high-temperature scanning tunneling microscopy. Armed with this equipment, it is possible to perform in-situ measurement up to 1300 K to obtain the growth formation of both graphene and h-BN on metal surfaces with a sub-nanometer resolution. Based on the previous result, the applicant proposes to: (1) develop a method for growing the composite material of graphene and h-BN; (2) investigate the influences of the growth condition to the film’s quality and functionality from the view of surface science; (3) simplify the production process of the materials and improve the material’s quality; 4) using graphene/h-BN composite material to fabricate field effect transistor and evaluate its performance. The success of the project will fill the gap of the growth combination material of graphene and h-BN. The theoretical analysis will enrich the knowledge of surface kinetics and dynamic and the production have industrial value.

石墨烯和单层六角氮化硼（h-BN）具有特殊的性质和广泛的应用前景，特别是这两种材料的复合能进一步提升石墨烯的性能。目前，石墨烯/h-BN复合材料的制备手段单一，常用分步生长转移法：先分别生长得到h-BN和石墨烯薄膜，再依次转移至目标基底。在前期工作中，申请者利用世界领先的高温扫描隧道显微镜对石墨烯以及h-BN的生长过程进行了原位观测，获得了亚纳米尺度上的生长动力学信息，为本项目的实施奠定了基础。本项目将开展以下工作：1）开发一步生长转移法制备石墨烯/h-BN复合材料；2）从表面科学角度分析生长条件对薄膜质量和性能的影响规律；3）利用理论结果，改善薄膜质量并简化其制备工艺；4）利用石墨烯/h-BN复合材料制备场效应晶体管并进行性能评价。本项目的成功实施将弥补国际上通过一步生长转移的方式制备石墨烯/h-BN复合材料的空白，对生长机理的理论分析将丰富表面科学的知识，所开发的产品具有产业化前景。

具有和石墨烯类似的原子结构的h-BN又成为人们心目中极为理想的石墨烯衬底材料，h-BN作为衬底材料有其他材料所不具备的优势：与石墨烯之间的晶格常数极为相近，失配只有1.8%;没有悬挂键及势肼，不会束缚电子并且h-BN同石墨烯的结合还能有效的打开石墨烯的带隙，提高开关比。目前，石墨烯/h-BN复合材料的制备手段单一，常用分步生长转移法：先分别生长得到h-BN和石墨烯薄膜，再依次转移至目标基底。本项目采用一步法合成石墨烯/h-BN复合材料，首先将Rh（111）样品放置于样品台上进行如上所述的表面清洁。随后，往真空腔中通入环硼氮烷至5*10-5~1*10-3mbar进行室温吸附，然后缓慢加热至1060K。生长过程结束后关闭加热器，旋转样品台至低温区实现快速降温，待降至室温后取出样品得到单层h-BN样品。本项目弥补了国际上通过一步生长转移的方式制备石墨烯/h-BN复合材料的空白，对生长机理的理论分析将丰富表面科学的知识，开发出的产品具有产业化前景。