Electronic transport across quantum dots in graphene nanoribbons: Toward built-in gap-tunable metal-semiconductor-metal heterojunctions

Abstract

The success of all-graphene electronics is severely hindered by the challenging realization and subsequent integration of semiconducting channels and metallic contacts. Here, we comprehensively investigate the electronic transport across width-modulated heterojunctions consisting of a graphene quantum dot of varying lengths and widths embedded in a pair of armchair-edged metallic nanoribbons, of the kind recently fabricated via on-surface synthesis. We show that the presence of the quantum dot enables the opening of a width-dependent transport gap, thereby yielding built-in one-dimensional metal-semiconductor-metal junctions. Furthermore, we find that, in the vicinity of the band edges, the conductance is subject to a smooth transition from an antiresonant to a resonant transport regime upon increasing the channel length. These results are rationalized in terms of a competition between quantum-confinement effects and quantum dot-to-lead coupling. Overall, our work establishes graphene quantum dot nanoarchitectures as appealing platforms to seamlessly integrate gap-tunable semiconducting channels and metallic contacts into an individual nanoribbon, hence realizing self-contained carbon-based electronic devices.

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• Unveiling and Manipulating Hidden Symmetries in Graphene Nanoribbons
• Electrically Induced Dirac Fermions in Graphene Nanoribbons
• One-dimensional magnetic conduction channels across zigzag graphene nanoribbon/hexagonal boron nitride heterojunctions
• Dirac half-semimetallicity and antiferromagnetism in graphene nanoribbon/hexagonal boron nitride heterojunctions
• Monolayer C${}_{60}$ networks: A first-principles perspective
• Even-odd conductance effect in graphene nanoribbons induced by edge functionalization with aromatic molecules: Basis for novel chemosensors
• Electronic structure of fullerene nanoribbons
• Zigzag nanoribbon of gated bilayer hexagonal crystals with spontaneous edge magnetism
• Quantum Electronic Transport Across "Bite" Defects in Graphene Nanoribbons
• Topological Interface States and Nonlinear Thermoelectric Performance in Armchair Graphene Nanoribbon Heterostructures
• Potential-tuned magnetic switches and half-metallicity transition in zigzag graphene nanoribbons