17 research outputs found
Ultrathick MAN(M'N) Intercalated Monolayers with Sublayer-Protected Fermi Surface Conduction States: Interconnect and Metal Contact Applications
Recent discovery of ultrathick monolayers open up
an exciting platform to engineer 2D material properties via intercalation
architecture. Here we computationally investigate a series of ultrathick
MAN(M'N) monolayers (M, M' = Mo, W; A = Si, Ge) under both homolayer
and heterolayer intercalation architectures in which the same and different
species of transition metal nitride inner core layers are intercalated by outer
passivating nitride sublayers, respectively. The MAN(M'N) monolayers
are thermally, dynamically and mechanically stable with excellent mechanical
strength and metallic properties. Intriguingly, the metallic states around
Fermi level are localized within the inner core layers. Carrier conduction
mediated by electronic states around the Fermi level is thus spatially
insulated from the external environment by the native outer nitride sublayers,
suggesting the potential of MAN(M'N) in back-end-of-line (BEOL) metal
interconnect applications. Nitrogen vacancy defect at the outer sublayers
creates `punch through' states around the Fermi level that bridges the carrier
conduction in the inner core layers and the outer environment, forming a
electrical contact akin to the `vias' structures of metal interconnects. We
further show that MoSiN(MoN) can serve as a quasi-Ohmic contact to 2D
WSe. These findings reveal the promising potential of ultrathick
MAN(MN) monolayers as metal electrodes and BEOL interconnect
applications.Comment: 13 pages, 7 figures, 3 table
MAZ Family Heteorstructures: Promises and Prospects
Recent experimental synthesis of ambient-stable MoSi2N4 monolayer have
garnered enormous research interests. The intercalation morphology of MoSi2N4 -
composed of a transition metal nitride (Mo-N) inner sub-monolayer sandwiched by
two silicon nitride (Si-N) outer sub-monolayers - have motivated the
computational discovery of an expansive family of synthetic MA2Z4 monolayers
with no bulk (3D) material counterpart (where M = transition metals or alkaline
earth metals; A = Si, Ge; and N = N, P, As). MA2Z4 monolayers exhibit
interesting electronic, magnetic, optical, spintronic, valleytronic and
topological properties, making them a compelling material platform for
next-generation device technologies. Furthermore, heterostructure engineering
enormously expands the opportunities of MA2Z4. In this review, we summarize the
recent rapid progress in the computational design of MA2Z4-based
heterostructures based on first-principle density functional theory (DFT)
simulations - a central \emph{work horse} widely used to understand the
physics, chemistry and general design rules for specific targeted functions. We
systematically classify the MA2Z4-based heterostructures based on their contact
types, and review their physical properties, with a focus on their performances
in electronics, optoelectronics and energy conversion applications. We review
the performance and promises of MA2Z4-based heterostructures for device
applications that include electrical contacts, transistors, spintronic devices,
photodetectors, solar cells, and photocatalytic water splitting. This review
unveils the vast device application potential of MA2Z4-based heterostructures,
and paves a roadmap for the future experimental and theoretical development of
MA2Z4-based functional heterostructures and devices.Comment: 32 pages, 15 figure
Redox-dependent Franck–Condon blockade and Avalanche Transport in a Graphene–Fullerene single-molecule transistor
We report transport measurements on a graphene–fullerene single-molecule transistor. The device architecture where a functionalized C60 binds to graphene nanoelectrodes results in strong electron–vibron coupling and weak vibron relaxation. Using a combined approach of transport spectroscopy, Raman spectroscopy, and DFT calculations, we demonstrate center-of-mass oscillations, redox-dependent Franck–Condon blockade, and a transport regime characterized by avalanche tunnelling in a single-molecule transistor
Graphene-porphyrin single-molecule transistors
We demonstrate a robust graphene-molecule-graphene transistor architecture. We observe remarkably reproducible single electron charging, which we attribute to insensitivity of the molecular junction to the atomic configuration of the graphene electrodes. The stability of the graphene electrodes allow for high-bias transport spectroscopy and the observation of multiple redox states at room-temperature
Single layer MoS2 nanoribbon field effect transistor
10.1063/1.5079860APPLIED PHYSICS LETTERS114
Deep learning-enabled prediction of 2D material breakdown
10.1088/1361-6528/abd655NANOTECHNOLOGY322
Conductance enlargement in picoscale electroburnt graphene nanojunctions
Provided the electrical properties of electroburnt graphene junctions can be understood and controlled, they have the potential to underpin the development of a wide range of future sub-10-nm electrical devices. We examine both theoretically and experimentally the electrical conductance of electroburnt graphene junctions at the last stages of nanogap formation. We account for the appearance of a counterintuitive increase in electrical conductance just before the gap forms. This is a manifestation of room-temperature quantum interference and arises from a combination of the semimetallic band structure of graphene and a cross-over from electrodes with multiple-path connectivity to single-path connectivity just before breaking. Therefore, our results suggest that conductance enlargement before junction rupture is a signal of the formation of electroburnt junctions, with a picoscale current path formed from a single sp2 bond
Back Cover: Toward Valley‐Coupled Spin Qubits (Adv. Quantum Technol. 6/2020)
10.1002/qute.202070063Advanced Quantum Technologies362070063-207006