Layered Two-Dimensional Heterostructures and Their Tunneling Characteristics

Beschreibung

This thesis demonstrates that layered heterostructures of two-dimensional crystals graphene, hexagonal boron nitride, and transition metal dichalcogenides provide new and interesting interlayer transport phenomena. Low-energy electron microscopy is employed to study the surface of atomically thin WSe2 prepared by metal-organic chemical vapor deposition on epitaxial graphene substrates, and a method for unambiguously measuring the number of atomic layers is presented. Using very low-energy electrons to probe the surface of similar heterostructures, a relationship between extracted work function differences from the layers and the nature of the electrical contact between them is revealed. An extension of this analysis is applied to surface studies of MoSe2 prepared by molecular beam epitaxy on epitaxial graphene. A large work function difference is measured between the MoSe2 and graphene, and a model is provided which suggests that this observation results from an exceptional defect density in the MoSe2 film. The thesis expounds a theory for computing tunneling currents between two-dimensional crystals separated by a thin insulating barrier; a few situations resulting in resonant tunneling and negative differential resistance are illustrated by computed examples, as well as observed characteristics, for monolayer and bilayer graphene tunneling junctions and transistors.
Nominated as an outstanding Ph.D. thesis by Carnegie Mellon University
Focuses on the timely topic of interlayer transport phenomena in two-dimensional materials
Describes a theory, illustrated with examples, for computing tunneling currents between two-dimensional crystals around a thin insulating barrier
Provides an introduction to the field whilst demonstrating interesting new results via theoretical and experimental perspectives


Nominated as an outstanding Ph.D. thesis by Carnegie Mellon University Focuses on the timely topic of interlayer transport phenomena in two-dimensional materials Describes a theory, illustrated with examples, for computing tunneling currents between two-dimensional crystals around a thin insulating barrier Provides an introduction to the field whilst demonstrating interesting new results via theoretical and experimental perspectives

Autor*in

Sergio C. de la Barrera

Themen in »Layered Two-Dimensional Heterostructures and Their Tunneling Characteristics«

resonant tunneling physics low-energy electron microscopy characterization of tungsten diselenide transition metal dichalcogenides epitaxial graphene work function extraction method interlayer tunneling Bardeen method 2D tunneling devices Graphene-Insulator-Graphene Tunnel Junctions

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