Sharp ballistic p–n junction at room temperature using Zn metal doping of graphene

Abstract

Ballistic graphene p–n junctions (GPNJs) are uniquely suited to develop electrical counterparts of optical circuits as the large transparency enables a better carrier modulation in their interfaces than the diffusive junctions. Here we demonstrate a low-cost and scalable method for the fabrication of ballistic planar GPNJs based on the deposition of physisorbed Zn adatoms. A detailed study of spatially resolved Raman spectroscopy through a quartz transparent substrate enables the accurate mapping of the charge doping and strain across the graphene/Zn interface and underneath the metal layer. At the same time, the electrical measurements of transistor structures with varying channel length, i.e. transfer length electrical measurements, and their modeling reveal the ballistic nature of the charge transport up to room temperature.