All-graphene electronics by exploiting physical analogies

Abstract

The concept of a bandgap is so deeply ingrained that it is hard to imagine an integrated circuit built on graphene, whose pristine state is a gapless material with charge carriers obeying the relativistic Dirac spectrum, analogous to light. Entertaining such notion is so appalling that many have proposed to cut graphene into bits and pieces, thinking that size quantization effect would recover a bandgap. Unfortunately, the edges are too disordered and unzipping nanotubes simply unzips more nightmares for device integration engineers. Embracing pristine graphene with its Dirac spectrum therefore appeals as a viable technological option worth careful investigation. Such “all-graphene electronics”, in which graphene is kept pristine and lithographic patterning is performed on the electrostatic gates or substrates instead, is the subject of this talk. To realize this, we have to demonstrate in pristine graphene at least two most basic elements of integrated circuit i.e. devices performing basic logic operations and interconnect that allows communication between them. In this talk, I will show through theory and simulations, and in some cases in corroboration with experiments, that the novel graphene electronic properties allow one to make interesting electronic devices based on analogies with optics and quantum Hall physics. In optics, one manipulates light beams through designs of refractive index of mediums. In graphene, the electron or hole density plays the role of refractive index instead. Strings of analogous electron optics devices such as Veselago lens, optical fiber, beam collimators can be realized in gapless graphene, thereby achieving spatial manipulation of electron beams leading to novel reconfigurable interconnects. In quantum Hall physics, it is well known that spatial separation of forward and backward going states leads to absence of back-scattering. In graphene, a large pseudo-magnetic field can be created through various novel strain geometries, and open up the possibility of low power computing devices. Here, we outline our proposal for all-graphene electronics and review our recent work described in [1–5] and also other related work described in the references of [1–5].