Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: IConductance of Graphene Nanoribbon Junctions and the Tight Binding Model | Wu and Childs Nanoscale Res Lett 2011 6 62 http content 6 1 62 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Conductance of Graphene Nanoribbon Junctions and the Tight Binding Model Y Wu PA Childs Abstract Planar carbon-based electronic devices including metal semiconductor junctions transistors and interconnects can now be formed from patterned sheets of graphene. Most simulations of charge transport within graphene-based electronic devices assume an energy band structure based on a nearest-neighbour tight binding analysis. In this paper the energy band structure and conductance of graphene nanoribbons and metal semiconductor junctions are obtained using a third nearest-neighbour tight binding analysis in conjunction with an efficient nonequilibrium Green s function formalism. We find significant differences in both the energy band structure and conductance obtained with the two approximations. Introduction Since the report of the preparation of graphene by Novoselov et al. 1 in 2004 there has been an enormous and rapid growth in interest in the material. Of all the allotropes of carbon graphene is of particular interest to the semiconductor industry as it is compatible with planar technology. Although graphene is metallic it can be tailored to form semiconducting nanoribbons junctions and circuits by lithographic techniques. Simulations of charge transport within devices based on this new technology exploit established techniques for low dimensional structures 2 3 . The current flowing through a semiconducting nanoribbon formed between two metallic contacts has been established using a nonequilibrium Green s Function NEGF formalism based coupled with an energy band structure derived using a tight binding Hamiltonian 4-7 . To minimise computation time the nearest-neighbour tight binding approximation is commonly used to determine the energy states and overlap is ignored. This assumption has also been used for
