Functionalized Two-Dimensional Nanoelectronic Heterostructures

Recent work has conclusively shown that the electronic properties of graphene can be exquisitely tuned through chemical modification. Similarly, the integration of graphene with other materials (e.g., high-k gate dielectrics) further modifies electronic properties due to changes in the local dielectric environment, scattering mechanisms, and trap states. This sensitivity to surface and interface chemistry can be traced to the atomically thin nature of graphene and suggests that the knowledge gained on graphene can be applied to other two-dimensional materials. Furthermore, these results imply opportunities for synergistically beneficial interactions if multiple two-dimensional materials are integrated into heterostructures. This research program includes a series of interrelated proposed directions that will employ atomically precise fabrication and characterization methods to understand and control the nanoelectronic properties of heterostructures based on two-dimensional materials including chemically functionalized graphene, ultrathin silicon, phosphorene, and transition metal dichalcogenides (TMDs). In all cases, the proposed chemistry will be characterized by a comprehensive set of experimental techniques ranging from atomic resolution ultra-high vacuum (UHV) scanning tunneling microscopy (STM) to direct charge transport measurements on lithographic defined devices. Through this integrated research approach, the design rules for functionalized two-dimensional nanoelectronic heterostructures will be delineated, thus impacting technologies with direct relevance for the Navy.