中文摘要：

石墨烯自从被发现以来,迅速引发了科学家的研究热潮.在石墨烯的诸多优异性质中,超高的电子迁移率使它在未来电子学产业中具有极大的应用前景.但是石墨烯是零带隙材料,极大地限制了它在电子学器件上的应用.在过去几年中,科学家不断从理论和实验上探索石墨烯打开带隙的方法,本文以是否直接破坏石墨烯的晶格或化学结构为依据,从两大类综述了石墨烯打开带隙的理论、计算和实验工作.

英文摘要：

Since the successful exfoliation of graphene monolayer, the exotic and superior electrical properties of graphene have rendered it a promising potential candidate for the future electronics. In particular, the extremely high electron mobility and the rapid developments in mass-fabricating high-quality graphene might initiate a new electronic industry revolution with graphene-based next-generation electronics, namely high-speed field effect transistors（FET）. However, the unique Dirac-conical band structure, which provides fascinating electronic features for graphene, turns out to be the primary obstacle that hinders the fabrication of graphene-based FET due to its lack of a band gap. Since a desirably large band gap is required for a high on-off ratio FET, physicists have been trying to figure out ways to open a controllable band gap in monolayer and multilayer graphene from the early stage of graphene research. Up till now, there are two major kinds of ways towards opening a band gap for graphene. The first is by directly violating the pristine electronic or geometrical properties of graphene, through doping, adatom, introducing periodic defects, constrictions, or other chemical treatments. These methods are generally destructive to graphene＇s original electronic properties. The other way largely preserves the pristine electronic properties of graphene, such as breaking the intrinsic symmetries of graphene that protect the Dirac cone intact, either through substrate interaction, applying external field, etc., or through other mechanisms such as spin-orbit interaction, strain, and electron many-body effects. There might be multiple mechanisms appearing in various theoretical or experimental works that contribute to the opening of band gap, and this classification is far from clear-cut. Investigations toward this problem include various methodologies, including theoretical proposition, ab-initio calculations, density-function or other approximated calculations, and experimental verification using angular reso