Lu, Nanshu | Search NASA

DOE OSTI2019

Appendage mountable electronic devices conformable to surfaces

Disclosed are appendage mountable electronic systems and related methods for covering and conforming to an appendage surface. A flexible or stretchable substrate has an inner surface for receiving an appendage, including an appendage having a curved surface, and an opposed outer surface that is accessible to external surfaces. A stretchable or flexible electronic device is supported by the substrate inner and/or outer surface, depending on the application of interest. The electronic device in combination with the substrate provides a net bending stiffness to facilitate conformal contact between the inner surface and a surface of the appendage provided within the enclosure. In an aspect, the system is capable of surface flipping without adversely impacting electronic device functionality, such as electronic devices comprising arrays of sensors, actuators, or both sensors and actuators.

Rogers, John A.↗

DOE OSTI2019

Evidence for moiré excitons in van der Waals heterostructures

Recent advances in the isolation and stacking of monolayers of van der Waals materials have provided approaches for the preparation of quantum materials in the ultimate two-dimensional limit(1,2). In van der Waals heterostructures formed by stacking two monolayer semiconductors, lattice mismatch or rotational misalignment introduces an in-plane moire superlattice(3). It is widely recognized that the moire superlattice can modulate the electronic band structure of the material and lead to transport properties such as unconventional superconductivity(4) and insulating behaviour driven by correlations(5-7); however, the influence of the moire superlattice on optical properties has not been investigated experimentally. Here we report the observation of multiple interlayer exciton resonances with either positive or negative circularly polarized emission in a molybdenum diselenide/tungsten diselenide (MoSe 2 /WSe 2 ) heterobilayer with a small twist angle. We attribute these resonances to excitonic ground and excited states confined within the moire potential. This interpretation is supported by recombination dynamics and by the dependence of these interlayer exciton resonances on twist angle and temperature. These results suggest the feasibility of engineering artificial excitonic crystals using van der Waals heterostructures for nanophotonics and quantum information applications.

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DOE OSTI2018

Appendage mountable electronic devices conformable to surfaces

Disclosed are appendage mountable electronic systems and related methods for covering and conforming to an appendage surface. A flexible or stretchable substrate has an inner surface for receiving an appendage, including an appendage having a curved surface, and an opposed outer surface that is accessible to external surfaces. A stretchable or flexible electronic device is supported by the substrate inner and/or outer surface, depending on the application of interest. The electronic device in combination with the substrate provides a net bending stiffness to facilitate conformal contact between the inner surface and a surface of the appendage provided within the enclosure. In an aspect, the system is capable of surface flipping without adversely impacting electronic device functionality, such as electronic devices comprising arrays of sensors, actuators, or both sensors and actuators.

42 ENGINEERING↗