University of California

Raytheon Company

Johns Hopkins University

University of Southern California

Roger Lake

Gary A Frazier

Alexander A Balandin

Alexander Khitun

Chia-ling Chien

Stephen B Cronin

Jing Shi

Yufan Li

Junxue Li

Mahesh Neupane

Rohan Dhall

Darshana Wickramaratne

Yadong Xu

Mohammed Aldosary

Chi Tang

Zhen Li

Jiadong Zang

Gen Yin

Bulk direct transition metal dichalcogenide (TMDC) may have an increased interlayer separation of at least 0.5, 1, or 3 angstroms more than its bulk value. The TMDC may be a bulk direct band gap molybdenum disulfide (MoS2) or a bulk direct band gap tungsten diselenide (WSe). Oxygen may be between the interlayers. A device may include the TMDC, such as an optoelectronic device, such as an LED, solid state laser, a photodetector, a solar cell, a FET, a thermoelectric generator, or a thermoelectric cooler. A method of making bulk direct transition metal dichalcogenide (TMDC) with increased interlayer separation may include exposing bulk direct TMDC to a remote (aka downstream) oxygen plasma. The plasma exposure may cause an increase in the photoluminescence efficiency of the TMDC, more charge neutral doping, or longer photo-excited carrier lifetimes, as compared to the TMDC without the plasma exposure.

Bulk direct gap MoS2 by plasma induced layer decoupling

Pure spin current devices are provided. The devices include sandwich structures of metal/magnetic insulator/metal. A first current injected in a first metal layer generates a pure spin current. The spin current can be switched between 'on' and 'off' states by controlling an in-plane magnetization orientation of the magnetic insulator. In the &#x201c;on&#x201d; state, the pure spin current is transmitted from the first metal layer to the second metal layer, through the magnetic insulator layer. The pure spin current in the second metal layer induces generation of a second charge current. In the &#x201c;off&#x201d; state, the pure spin current is absorbed at the interface between the first metal layer and the metal insulator. Such structures can serve as pure spin current valve devices or provide analog functionality, as rotating the in-plane magnetization provides analog sinusoidal modulation of the spin current.

Spin current devices and methods of fabrication thereof

A method for generating a skyrmion, comprising: depositing a vertical metallic nanopillar electrode on a first side of a helimagnetic thin film, the helimagnetic thin film having a contact on a second side to provide a current drain; injecting a current through the vertical metallic nanopillar electrode to generate a rotating field; and applying a static upward magnetic field perpendicular to the helimagnetic thin film to maintain an FM phase background.

Skyrmion based universal memory operated by electric current

A dual-gate transistor having a negative differential resistance (NDR) region is disclosed. The dual-gate transistor includes a back-gate, a zero-bandgap graphene layer disposed on the back-gate, a top-gate disposed on a portion of the zero-bandgap graphene layer adjacent to the top-gate, and a drain disposed on a portion of the zero-bandgap graphene layer adjacent to the top-gate and displaced from the source. Also included is a dynamic bias controller configured to simultaneously sweep a source-drain voltage and a top-gate voltage across a Dirac point to provide operation within the NDR region. Operation within the NDR region is employed to realize non-Boolean logic functions. Graphene-based non-Boolean logic circuits are constructed from pluralities of the disclosed dual-gate transistor. Pattern recognition circuitry for operation between 100 GHz and 500 GHz is also disclosed via the graphene-based non-Boolean logic circuits.

Graphene-based non-boolean logic circuits

According to one embodiment of the invention, a digital to analog converter for converting a digital signal to an analog optical signal includes a light source and a plurality optical switches. Each optical switch is responsive to a respective one of a plurality of bits of a digital signal to selectively allow transmission of light from the light source through the switch. The digital to analog converter also includes a light combination system operable to combine the light passed through each of the switches and produce an analog optical signal indicative of the digital signal.

Optical digital to analog converter

Growing community of inventors

Riverside, CA, United States of America

Roger Lake