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Pennsylvania State University
MBE epitaxy tool with in vacuo cryogenic ARPES and 4 probe STM
The Thin Films and In Situ Characterization Facility in the 2D Crystal Consortium – Materials Innovation Platform (2DCC-MIP) user facility includes a multimodule ultra-high vacuum system for the synthesis and study of two dimensional (2D) chalcogenide films by molecular beam epitaxy (MBE).
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Pennsylvania State University
Fano resonances from plasmon-exciton coupling in hetero-bilayer WSe2-WS2 on Au nanorod arrays
Plasmon-exciton coupling in hetero-bilayer of WSe2 and WS2 transferred onto Au nanorod arrays is studied. Dark-field scattering measurements reveal that the in-plane dipole moment of excitons in monolayer WS2 allows only the narrow spectral range of 30 nm for the resonant coupling between the localized particle plasmons from Au nanorods and the bright excitons from WS2. We demonstrate that the q-parameter that represents the asymmetry of Fano resonances from plasmon-exciton coupling can be controlled by the polarization states of incident light. Surface lattice resonances in between individual Au nanorods play a role to diminish the damping factor of plasmon-exciton coupling in the arrays.
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Pennsylvania State University
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.
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Pennsylvania State University
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.
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Pennsylvania State University
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.
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Pennsylvania State University
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.
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Pennsylvania State University
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).
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Pennsylvania State University
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.
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Pennsylvania State University
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.
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