▎ 摘　　要

Graphene is the recently discovered two-dimensional (2D) one atom thick allotrope of carbon. Electrons in graphene, obeying a linear dispersion relation, behave like massless relativistic particles. It is a 2D nanomaterial with many peculiar properties. It is the thinnest material in the universe and the strongest ever measured. Its charge carriers exhibit intrinsic mobility and can travel micrometer-long distances without scattering at room temperature. Its unconventional Landau level spectrum of massless Dirac fermions leads to a new type of integer quantum Hall effect (IQHE) [known as half-integer quantum Hall effect or anomalous quantum Hall effect] which remains visible up to room temperature. Although, the conclusive evidence for collective behaviour of electrons in graphene is lacking so far, recently scientists have observed the fractional quantum Hall effect (FQHE) in graphene experimentally. In this review article, we discuss the IQHE and the FQHE in graphene briefly.