One-dimensional edge contacts to a monolayer semiconductor

Abstract

Integration of electrical contacts into van der Waals (vdW) heterostructures is critical for realizing electronic and optoelectronic functionalities. However, to date no scalable methodology for gaining electrical access to buried monolayer two-dimensional (2D) semiconductors exists. Here we report viable edge contact formation to hexagonal boron nitride (hBN) encapsulated monolayer MoS${}_2$. By combining reactive ion etching, in situ Ar${}^{+}$ sputtering and annealing, we achieve a relatively low edge contact resistance, high mobility (up to ~30 cm${}^2$/Vs) and high on-current density (>50 uA/um at V${}_{\mathrm{DS}}$ = 3V), comparable to top contacts. Furthermore, the atomically smooth hBN environment also preserves the intrinsic MoS${}_2$ channel quality during fabrication, leading to a steep subthreshold swing of 116 mV/dec with a negligible hysteresis. Hence, edge contacts are highly promising for large-scale practical implementation of encapsulated heterostructure devices, especially those involving air sensitive materials, and can be arbitrarily narrow, which opens the door to further shrinkage of 2D device footprint.

Supplementary Information file included

References in corpus (27)

• Boron nitride substrates for high-quality graphene electronics
• Robust memristors based on layered two-dimensional materials
• Improved Contacts to MoS2 Transistors by Ultra-High Vacuum Metal Deposition
• Quality heterostructures from two dimensional crystals unstable in air by their assembly in inert atmosphere
• Towards barrier free contact to MoS2 using graphene electrodes
• Spontaneous doping of the basal plane of MoS2 single-layers through oxygen substitution under ambient conditions
• Quantum engineering of transistors based on 2D materials heterostructures
• Band-Like Transport in High Mobility Unencapsulated Single-Layer MoS2 Transistors
• Boron nitride nanoresonators for phonon-enhanced molecular vibrational spectroscopy at the strong coupling limit
• Atomically thin p-n junctions based on two-dimensional materials
• Chemical assembly of atomically thin transistors and circuits in a large scale
• Low Frequency Electronic Noise in Single-Layer MoS2 Transistors
• Atomically-thin Ohmic Edge Contacts Between Two-dimensional Materials
• Switching Mechanism in Single-Layer Molybdenum Disulfide Transistors: an Insight into Current Flow across Schottky Barriers
• Parallel Stitching of Two-Dimensional Materials
• Minimizing Residues and Strain in 2D Materials Transferred from PDMS
• Defect Tolerant Monolayer Transition Metal Dichalcogenides
• Immunity to Scaling in MoS2 Transistors Using Edge Contacts
• Strain Mapping of Two-Dimensional Heterostructures with Sub-Picometer Precision
• Uncovering edge states and electrical inhomogeneity in MoS2 field-effect transistors
• Universal low-temperature Ohmic contacts for quantum transport in transition metal dichalcogenides
• Via Method for Lithography Free Contact and Preservation of 2D Materials
• Superconducting properties of corner-shaped Al microstrips
• Electron transport through metal/MoS2 interfaces: edge- or area-dependent process?
• N- and p-type carrier injections into WSe2 with van der Waals contacts of two-dimensional materials
• One-dimensional ferromagnetic edge contacts to two-dimensional graphene/h-BN heterostructures
• Bilayer h-BN Barriers for Tunneling Contacts in Fully-Encapsulated Monolayer $\mathbf{MoS}{\mathbf{e}}_2$ Field-Effect Transistors

Cited by in corpus (4)

• Machine learning driven synthesis of few-layered WTe2
• Electron transport through metal/MoS2 interfaces: edge- or area-dependent process?
• Low-Temperature 2D/2D Ohmic Contacts in WSe${}_2$ Field-Effect Transistors as a Platform for the 2D Metal-Insulator Transition
• One-Dimensional Edge Contact to Encapsulated MoS2 with a Superconductor