Nanoscale Electrical Transfer and Coherent Transport Between Atomically-Thin Materials

The working paradigm of the electronics field over the last 50 years has been the steady reduction in size of their components, yet as the size of electronics are reduced towards nanoscale dimensions electrical contacts are increasingly important, and their resistances are major obstacles to achieving faster and more efficient devices. It is widely expected that this steady reduction in size will soon involve the incorporation of the new class of atomically-thin materials (such as, graphene, nanotubes, and the dichalcogenides) into future electronics. At this extreme limit of miniaturization, the interfaces to electrical contacts will likely become the critical barriers to improved performances and energy efficiencies. The case in which both the device material and the contact comprise an atomically-thin material is particularly exciting, however, as this nanostructure has the potential to realize controlled coherent transport at the electrode-channel interface, enabling very high conductivities over extremely short length scales; in essence pushing the limit of miniaturization of the electrode thickness can in this situation be exploited as an advantage rather than being an obstacle. The objective of this project is to utilize highly-ordered atomically-thin commensurate nanoscale electrodes to probe and control the coherent electron transfer to another atomically-thin material. To fulfill the objective, two aims will be pursued to determine the electron transport between commensurate electrodes through channel materials comprising two prototypical atomically-thin materials with different dimensionalities; one-dimensional nanotubes, and atomically-thin 2D materials. This two-aim research effort will provide fundamental complementary understanding of coherent transfer processes as the dimensionality of the electrical interface is varied. The investigations are expected to yield important insight into (1) How the interplay of the key material parameters at the atomically-thin interface governs quantum coherent transfer; (2) The resulting characteristic length and energy scales of the electron transfer at interfaces of atomically-thin materials; and (3) The key parameters controlling the resulting coherent electron transfer at interfaces to atomicallythin materials using a subset of externally applied controls. The collective attainment of these outcomes will provide detailed understanding of the quantum transport processes to the thinnest possible materials and the interplay between the relevant length and energy scales in the vicinity of their interfaces. It is expected that this insight could lead to control of useful phenomena, such as negative differential resistance, which may be of use in novel high-speed devices; or, in contrast, this understanding may help in reducing deleterious resistances that slow response times of devices and cause wasteful energy dissipation and Joule heating. The improvements in performance, functionality, and efficiency that should derive from the proposed fundamental investigation are of broad importance to DOE’s mission and programmatic needs.