First Principles Study of Band Structure and Band Gap Engineering in Graphene for Device Applications.

摘要

Graphene, the super carbon , is now accepted as wonder material with new physics and it has caused major breakthrough in nanotechnology[1-3]. Graphene has been the main candidate for applications in semiconductor electronics and in other related fields [4-7]. After a decade of the discovery of graphene [7] , one may have to answer the following questions. Are the key technological huddles overcome successfully to realise the full applications of graphene? What is the current status of the graphene based devices or Electronics ? How the graphene market business is going to evolve in the coming years? What kind of graphene based products can one expect in the near future?. The main challenge in graphene is the opening of the band gap in the semimetallic electronic structure. In the bandstructure of graphene which is dominated by Dirac description, valence and conduction bands cross the Fermi level at a single point (K points) in the Brillouin zone and hence it is a is a zero gap semiconductor or a semimetal with zero density of states . Due to the linear dispersion of energy bands and appearance of Dirac cones near the K point and Fermi level the electrons behave like massless Dirac fermions [1]. For applications in nanoelectronic devices a suitable band gap is essential. Opening a suitable bandgap in graphene will allow it to be used in the semiconductor industry for the fabrication of new 2-dimensional nanoelectronic devices such as solar cells, liquid crystal devices, and nanosized transistor prototypes [8].