中文摘要：

石墨烯是一种单原子层的二维材料，因其独特的晶格结构而具备十分优越的性能，引起了科学家的广泛关注。但因其价带与导带相交于狄拉克点，导致石墨烯为没有带隙的半金属，限制了其在纳电子学器件中的应用。为了打开石墨烯的带隙，研究者们付出了巨大的努力。在石墨烯中引入带隙的方法包括量子限制法、掺杂法和对称性破缺法，它们分别是将电子限制在一维的石墨烯纳米带中、对石墨烯进行住．型或p-型掺杂以及在双层石墨烯的垂直方向施加外加电场使双层石墨烯的对称性破缺。本文着重介绍石墨烯纳米带的合成法、石墨烯掺杂的种类和打破双层石墨烯对称性的方法。

英文摘要：

Graphene, a single atomic layer, is a kind of two-dimensional material, and it has aroused widespread concern. Graphene shows excellent physical and chemical properties because of its unique lattice structure. However, conduction band of graphene intersects with its valence band on the Dirac point, thus graphene exhibits a zero-band gap with linear band dispersion at the Fermi-level, limiting its application in nanoelectronic devices area. To solve the problem of the band gap of graphene, researchers have paid a tremendous effort. The way commonly used to in- troduce the band gap of graphene is quantum confinement, doping method, and twisted symmetry method. The ways introducing bandgap of graphene include electron limited in one-dimensional graphene nanoribbons, graphene conducted n-type or p-type doping and an applied electric field in the vertical direction in bilayer graphene to twist symmetry. Therefore, this article focuses on the preparation of graphene nanoribbons, graphene doping type, and introduction of how to twist symmetry in bilayer graphene.