A Numerical Study of Graphene Nano-ribbon Based Resonant Tunneling Diodes

The many desirable material properties of the novel graphene films, including ultra-high mobility, high saturation velocity, high current carrying capability, excellent thermal conductivity, ultra-thin geometry, and the feature to integrate with traditional CMOS processes, offer the potential for graphene-based electronics. Since the bandgap of semiconducting GNRs is inversely proportional to their width, hetero-junctions using GNRs of different widths can be envisioned. A rich variety of bandgaps in GNRs has been discussed in [1]. They are either metals or semiconductors depending on their edge shape and width. Two nano-ribbon segments with different atomic and electronic structures can be seamlessly fused together to create intermolecular metal-metal, metal-semiconductor, or semiconductor-semiconductor junctions. Moreover, periodically repeating hetero-junctions of different widths can form superlattices [2]. Since nano-ribbons with a width less than 10 nm with uniform and patterned edges have been produced [3], present results related with graphene based nano-ribbons and their hetero-junctions of diverse geometry can, in fact, be a candidate for a class of nano-devices with a richness of novel properties.