▎ 摘　　要

The authors present an overview of the main theoretical approaches used to describe tunnel processes in graphene nanoelectronics. Two currently central theoretical methods of calculating tunnel current, the Bardeen tunneling Hamiltonian approach and the method of nonequilibrium Green's functions, are reviewed in a pedagogical fashion. Several examples are used to illustrate the specific features of the methods. An application of both methods to the analysis of current flow in graphene tunnel field-effect transistors is discussed. (C) 2017 Author(s).