Ultra Low Specific Contact Resistivity in Metal-Graphene Junctions via Atomic Orbital Engineering

Abstract

A systematic investigation of graphene edge contacts is provided. Intentionally patterning monolayer graphene at the contact region creates well-defined edge contacts that lead to a 67% enhancement in current injection from a gold contact. Specific contact resistivity is reduced from 1372 Ωm for a device with surface contacts to 456 Ωm when contacts are patterned with holes. Electrostatic doping of the graphene further reduces contact resistivity from 519 Ωm to 45 Ωm, a substantial decrease of 91%. The experimental results are supported and understood via a multi-scale numerical model, based on density-functional-theory calculations and transport simulations. The data is analyzed with regards to the edge perimeter and hole-to-graphene ratio, which provides insights into optimized contact geometries. The current work thus indicates a reliable and reproducible approach for fabricating low resistance contacts in graphene devices. We provide a simple guideline for contact design that can be exploited to guide graphene and 2D material contact engineering.

arXiv comment26 pages

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• Graphene in 2D/3D Heterostructure Diodes for High Performance Electronics and Optoelectronics
• Exploiting ambipolarity in graphene field-effect transistors for novel designs on high-frequency analog electronics
• Reducing the metal-graphene contact resistance through laser-induced defects
• Graphene-Quantum Dot Hybrid Photodetectors from 200 mm Wafer Scale Processing
• Transit-time resonances enabling amplification and generation of terahertz radiation in periodic graphene p-i-n structures with the Zener-Klein interband tunneling
• Large responsivity of graphene radiation detectors with thermoelectric readout