石墨烯纳米结构的制备及带隙调控研究

石墨烯在未来微电子学领域有极大的应用前景,但是其零带隙的特点阻碍了石墨烯在半导体领域的应用.研究发现,打开室温下可用的石墨烯带隙所需要的石墨烯纳米结构尺度在10 nm以下,这一尺度的纳米结构一方面制备比较困难,另一方面器件可承载的驱动电流较小.因此,如何实现亚10 nm石墨烯纳米结构的有效加工以及如何在有效调控带隙的基础上增大石墨烯器件可承载的驱动电流,还需要进一步的研究.本文首先研究了利用聚甲基丙烯酸甲酯/铬(PMMA/Cr)双层结构工艺,通过刻蚀时间的控制,利用电子束曝光及刻蚀工艺实现了亚10 nm石墨烯纳米结构的可控制备.同时设计并制备了单排孔石墨烯条带结构,该结构打开的带隙远大于相同特征宽度石墨烯纳米带所能打开带隙的大小.该结构在有效打开石墨烯带隙的同时,增加了石墨烯纳米结构可以承载的驱动电流,有利于石墨烯在未来微电子领域的应用.

Fabrication of graphene nanostructure and bandgap tuning

Graphene has potential applications in future microelectronics due to its novel electronic and mechanical properties. However, the lack of the bandgap in graphene poses a challenge and hinders its applications. In order to be able to work in ambient condition, gap engineering of graphene with nanostructure needs about sub-10 nm characteristic size, which increases the difficulty of fabrication and leads to less driving current that can be borne. In this paper, a new method to fabricate sub-10 nm graphene nanostructures is developed. With PMMA/Cr bilayer structure, sub-10 nm graphene nanostructures can be obtained precisely and repeatedly through controlling the etching time. Meanwhile, a new device based on graphene nanoconstrictions connected in parallel is designed and fabricated, whose band gap is bigger than that of graphene nanoribbon and whose characteristic width is the same as that of graphene nanoribbon. With the graphene nanoconstrictions connected in parallel, the band gap of the graphene can be adjusted effectively and the driving current can be significantly increased, which is very important for future practical applications of graphene.