Charge-transfer Contact to a High-Mobility Monolayer Semiconductor

Abstract

Two-dimensional (2D) semiconductors, such as the transition metal dichalcogenides, have demonstrated tremendous promise for the development of highly tunable quantum devices. Realizing this potential requires low-resistance electrical contacts that perform well at low temperatures and low densities where quantum properties are relevant. Here we present a new device architecture for 2D semiconductors that utilizes a charge-transfer layer to achieve large hole doping in the contact region, and implement this technique to measure magneto-transport properties of high-purity monolayer WSe${}_2$. We measure a record-high hole mobility of 80,000 cm${}^2$/Vs and access channel carrier densities as low as $1.6\times 10^{11}$ cm${}^{-2}$, an order of magnitude lower than previously achievable. Our ability to realize transparent contact to high-mobility devices at low density enables transport measurement of correlation-driven quantum phases including observation of a low temperature metal-insulator transition in a density and temperature regime where Wigner crystal formation is expected, and observation of the fractional quantum Hall effect under large magnetic fields. The charge transfer contact scheme paves the way for discovery and manipulation of new quantum phenomena in 2D semiconductors and their heterostructures.

References in corpus (32)

• Signatures of Fractional Quantum Anomalous Hall States in Twisted MoTe2 Bilayer
• Observation of Fractionally Quantized Anomalous Hall Effect
• Possible Metal/Insulator Transition at B=0 in Two Dimensions
• Quantum anomalous Hall effect from intertwined moiré bands
• Integer and fractional Chern insulators in twisted bilayer MoTe2
• High-Mobility Holes in Dual-Gated WSe${}_2$ Field-Effect Transistors
• Strongly correlated excitonic insulator in atomic double layers
• Observation of Wigner crystal of electrons in a monolayer semiconductor
• Shubnikov-de Haas oscillations of high mobility holes in monolayer and bilayer WSe${}_2$: Landau level degeneracy, effective mass, and negative compressibility
• Phase Diagram of the Low-Density Two-Dimensional Homogeneous Electron Gas
• Ultra-high quality two-dimensional electron systems
• Universal low-temperature Ohmic contacts for quantum transport in transition metal dichalcogenides
• Mapping twist-tuned multiband topology in bilayer WSe${}_2$
• Large effective mass and interaction-enhanced Zeeman splitting of $K$-valley electrons in MoSe${}_2$
• Graphene/$\alpha$-RuCl${}_3$: An Emergent 2D Plasmonic Interface
• Spin-split band hybridization in graphene proximitized with $\alpha$-RuCl${}_3$ nanosheets
• Odd- and even-denominator fractional quantum Hall states in monolayer WSe${}_2$
• Modulation Doping via a 2d Atomic Crystalline Acceptor
• Competing correlated states around the zero field Wigner crystallization transition of electrons in two-dimensions
• Quantitative transport measurements of fractional quantum Hall energy gaps in edgeless graphene devices
• Bridging the gap between atomically thin semiconductors and metal leads
• Gate-tunable flat bands in van der Waals patterned dielectric superlattices
• Multivalley two-dimensional electron system in an AlAs quantum well with mobility exceeding $2\times 10^6$ cm${}^2$V${}^{-1}$s${}^{-1}$
• Direct Measurement of the g-Factor of Composite Fermions
• Record-quality GaAs two-dimensional hole systems
• Scattering mechanisms in state-of-the-art GaAs/AlGaAs quantum wells
• Density-tuned effective metal-insulator transitions in 2D semiconductor layers: Anderson localization or Wigner crystallization
• Interplay between Quantum Well Width and Interface Roughness for Electron Transport Mobility in GaAs Quantum Wells
• Perfect Coulomb drag in a dipolar excitonic insulator
• Perfect Coulomb drag and exciton transport in an excitonic insulator
• Two-step flux synthesis of ultrapure transition metal dichalcogenides
• Transport Study of Charge Carrier Scattering in Monolayer WSe${}_2$

Cited by in corpus (13)

• Superconductivity in twisted bilayer WSe${}_2$
• Non-Abelian fractionalization in topological minibands
• Contact resistance and interfacial engineering: Advances in high-performance 2D-TMD based devices
• Direct measurement of terahertz conductivity in a gated monolayer semiconductor
• Angle evolution of the superconducting phase diagram in twisted bilayer WSe2
• Apparent inconsistency between Streda formula and Hall conductivity in reentrant integer quantum anomalous Hall effect in twisted MoTe${}_2$
• Interface engineering of van der Waals heterostructures towards energy-efficient quantum devices operating at high temperatures
• Density-dependent spin susceptibility and effective mass in monolayer MoSe2
• Tuning transport in solid-state Bose-Fermi mixtures by Feshbach resonances
• Efficient and Robust p-type Transistor based on Ultra-wide-bandgap Semiconductor
• Transconductance as a Probe of Valley Thermodynamics in Multilayer WSe${}_2$
• Universal transport at Lifshitz metal-insulator transitions in two dimensions
• Cascade of fractional quantum Hall states in 2D system