Lifetime Sample Tracking

Under LiST, data follow the sample from substrate preparation to synthesis protocol, integrated UHV characterization, ex situ characterization, modeling, delivery, and publication, with fine-grained access control and community-accessible tools and data.

Interlayer Magnetophononic Coupling in MnBi,Te4

STEP FORWARD

Geospatial tool built on Google Maps API to identify MSI, PUI and non-R1 institutions along existing travel itineraries. Facilitates user outreach to a diverse range of institutions through travel extension. Higher Education R&D data highlights institutions active in research fields of interest.

Precursors for Carbon-Free Transition Metal Dichalcogenide (TMD) Films

Transition metal dichalcogenides (TMDs) such as WS2 exhibit intriguing properties in monolayer form including direct bandgaps and large exciton binding energies. A major challenge in harnessing their potential is the uniform growth of high quality monolayers over large substrate areas. In this work, the 2DCC-MIP team investigated the effect of the choice of chalcogen precursors in a cold-wall reactor geometry for the specific case of WS2.

Wafer scale epitaxial growth of unidirectional WS2 monolayers on sapphire

Realization of wafer-scale single-crystal films of transition metal dichalcogenides (TMDs) such as WS2 requires epitaxial growth and coalescence of oriented domains to form a continuous monolayer. The domains must be oriented in the same crystallographic direction on the substrate to inhibit the formation of inversion domain boundaries (IDBs), which form when oppositely oriented triangular domains coalesce.

Stochastic Resonance In MoS2 Photodetector

In this project, we use a novel approach for next generation ultra-low-power sensor design by embracing the evolutionary success of animals with extraordinary sensory information processing capabilities that allow them to survive in extreme and resource constrained environments. Stochastic resonance (SR) is one of those astounding phenomena, where noise, which is considered detrimental for electronic circuits and communication systems, plays a constructive role in the detection of weak signals. Here, we show SR in a photodetector based on wafer-scale monolayer MoS2 for detecting ultra-low-intensity subthreshold optical signals from a distant light emitting diode (LED).

Phonons and excitons in ZrSe2 – ZrS2 alloys

ZrS2 has received increased attention due to its indirect band gap that matches with the visible spectrum and which is predicted to undergo an indirect-to-direct transition with strain. Alloying with ZrSe2 to produce ZrSxSe2-x (x=0...2) would provide continuous control over key optical and electronic parameters for photonics.

Can Ripples In Monolayer Sheets “Sweep Out” Unwanted Defects?

Atomically thin two-dimensional layers such as molybdenum disulfide, MoS2, are promising materials for nanoelectronics due to their exceptional electronic and optical properties. An inter-atomic potential has been developed that can accurately describe the thermodynamic and structural properties of MoS2 sheets, including defects and transitions between different structural phases.

Deterministic Quantum Emission in an Epitaxial Two-Dimensional Material

LANL CINT scientists and their collaborators at UConn, AFRL, Penn State, and U. Oregon have discovered a method to create spatially localized quantum emission sites in a wafer-scale transition metal dichalcogenide film, WSe2, synthesized at the 2DCC facility. The team’s objective was to determine the role of strain in creating localized quantum emission sites in order to learn how to control their properties through strain.

Two-Dimensional Grain Boundaries By Design

Grain boundaries are borders that separate crystals of distinct orientations and are generally considered as inevitable by-products of crystalline regions nucleating at different locations during growth. The MIP team has predicted how grain boundaries in two-dimensional crystals can form within a single grain by introducing bumps onto the substrate – the “floor” on which a 2D crystal grows.

Electronic changes in molybdenum dichalcogenides on gold surfaces

In this study, x-ray and ultraviolet photoelectron spectroscopy (XPS, UPS) were used to identify charge transfer processes and changes in the structural phase for MoS2, MoSe2 and MoTe2 monolayers on Au surfaces annealed up to 500oC.

Atomically Thin Stripes in Monolayer Sheets

The chemical similarity of molybdenum & tungsten suggests they should randomly distribute in WxMo1-xS2, a material of great interest for next-generation elec-tronics. The 2DCC discovered that these atoms actually form thin chains, whose very different masses make properties like heat conduction anisotropic. Stripes form due to fluctuations in the availability of sulfur, the third element in WxMo1-xS2.