USA As Represented by Secretary of the Navy

University System of Maryland

Beijing University of Technology

Massachusetts Institute of Technology

Rohm Co., Ltd.

University of Massachusetts

Georgetown University

Universidade Federal Do Rio Grande Do Sul-ufrgs

David Kurt Gaskill

Rachael L Myers-Ward

Charles R Eddy, Jr

Virginia D Wheeler

Robert E Stahlbush

Glenn Jernigan

Evgeniya H Lock

Nelson Garces

Anindya Nath

Brenda L VanMil

F Keith Perkins

Michael Sears Fuhrer

Nadeemmullah A Mahadik

Howard Dennis Drew

Kok-Keong Lew

Anthony K Boyd

Thomas E Murphy

Andrei B Sushkov

Mohammad M Jadidi

Christos Dimitrios Dimitrakopoulos

Anna Leese De Escobar

David A Stenger

Scott A Trammell

Daniel Zabetakis

Scott G Walton

Marc Currie

Michael S Osofsky

Raymond C Y Auyeung

Richard L Henry

Alan D Berry

Edward J Cukauskas

Osama M Nayfeh

Takuji Maekawa

Ronald T Holm

Joseph C Prestigiacomo

Wei Kong

Paola Barbara

Patrick Craig Sims

Sandra C Hangarter

Dimitrios Maroudas

Noriyuki Masago

Raphael Kaplan

Andre R Muniz

Xinghan Cai

Tom Reinecke

Sam Carter

Brad Liu

Abdel El Fatimy

Kuan Qiao

Jeehwan Kim

Systems and methods for growth of silicon carbide over a layer comprising graphene and/or hexagonal boron nitride, and related articles, are generally described. In some embodiments, a SiC film is fabricated over a layer comprising graphene and/or hexagonal boron nitride, which in turn is disposed over a substrate. The layer and/or the substrate may be lattice-matched with the SiC film to reduce defect density in the SiC film. The fabricated SiC film may then be removed from the substrate via, for example, a stressor attached to the SiC film. In certain cases, the layer serves as a reusable platform for growing SiC films and also serves a release layer that allows fast, precise, and repeatable release at the layer surface.

Systems and methods for growth of silicon carbide over a layer comprising graphene and/or hexagonal boron nitride and related articles

A sensitive and selective, in-line method to measure and validate the sulfur content at ppb levels in both the liquid and gas phase of an analyte. The method includes patterning graphene, for example to form a mesa structure comprising horizontal or vertical lines or an array of multidentate star features; functionalizing the patterned graphene and attaching nanoparticles to the functionalized graphene to form a device; exposing the device to an analyte in the gas or liquid phase; detecting a change in electrical response when sulfur is present in the analyte; and recovering the device for future use. Also disclosed is the related sulfur detector.

Graphene-based PPB level sulfur detector

A method for graphene functionalization that preserves electronic properties and enables nanoparticles deposition comprising providing graphene, functionalizing the graphene via non-covalent or covalent functionalization, rinsing the graphene, drying the graphene, and forming functionalized graphene wherein the functionalized graphene preserves electronic properties and enables nanoparticles deposition. A functionalized graphene wherein the graphene functionalization preserves electronic properties and enables nanoparticles deposition.

Method for graphene functionalization that preserves characteristic electronic properties such as the quantum hall effect and enables nanoparticles deposition

Devices including graphene quantum dots yield extremely high performance THz bolometers, by measuring the current of hot electrons formed in the graphene source and drain electrodes of the device and propagating through the graphene quantum dot connected thereto. Devices may also include additional materials such as MoS, as well as one or more gate electrodes to alter performance as needed.

Epitaxial graphene quantum dots for high-performance terahertz bolometers

A sensitive and selective, in-line method to measure and validate the sulfur content at ppb levels in both the liquid and gas phase of fuel. The method includes etching graphene, for example to form a mesa structure comprising horizontal or vertical lines or an array of multidentate star features; functionalizing the etched graphene and attaching metal oxide nanoparticles to the functionalized graphene to form a device; exposing the device to a fuel in the gas or liquid phase; detecting a change in conductivity when sulfur is present in the fuel; and recovering the device for future use. Also disclosed is the related in-line graphene-based ppb level sulfur detector for fuels.

Graphene-based PPB level sulfur detector in fuels

An electrochemical cell includes a working electrode in contact with an aqueous electrolyte solution, a counter electrode in contact with the aqueous electrolyte solution, and a reference electrode in contact with the aqueous electrolyte solution. The working electrode comprises a plasma modified epitaxial synthesized graphene surface fabricated on SiC.

Plasma modified epitaxial fabricated graphene on SiC for electrochemical trace detection of explosives

An article of manufacture includes a first graphene layer, a second graphene layer over the first graphene layer, the second graphene layer oriented at a first interlayer twist angle with respect to the first graphene layer and bonded by interlayer covalent bonds to the first graphene layer, and a third graphene layer over the second graphene layer, the third graphene layer oriented at a second interlayer twist angle with respect to the second graphene layer and bonded by interlayer covalent bonds to the second graphene layer. A multi-layer graphene article includes at least three graphene layers, each graphene layer being oriented at an interlayer twist angle with respect to an adjacent graphene layer and bonded by interlayer covalent bonds to the adjacent graphene layer.

Multilayer graphene structures with enhanced mechanical properties resulting from deterministic control of interlayer twist angles and chemical functionalization

A new approach to graphene-enabled plasmonic resonant structures in the THz is demonstrated in a hybrid graphene-metal design in which the graphene acts as a gate-tunable inductor, and metal acts as a capacitive reservoir for charge accumulation. A large resonant absorption in graphene can be achieved using the metal-graphene plasmonic scheme, and the peak can approach 100% in an optimized device, ideal for graphene-based THz detectors. Using high mobility graphene (&#x3bc;&#x3e;50000 cmVs) will allow anomalously high resonant THz transmission (near 100%) through ultra-subwavelength graphene-filled metallic apertures at a resonance frequency that is gate tunable. This metal-graphene plasmonic scheme enables near perfect tunable THz filter or modulator.

Hybrid metal-graphene terahertz optoelectronic system with tunable plasmonic resonance and method of fabrication

A method includes depositing a layer of silicon oxide onto a layer of silicon carbide; ion implanting the layer of silicon carbide, annealing the ion implanted layer of silicon carbide to produce defects within the layer of silicon carbide, performing photolithography using a mask layer on regions of the layer of silicon carbide to define regions for electrode deposition, removing the layer of silicon oxide from the layer of silicon carbide in the one or more regions for electrode deposition, forming one or more electrodes by depositing indium tin oxide (ITO) in each of the regions for electrode deposition, performing a first lift-off operation to remove the mask layer surrounding the electrodes, depositing a passivation and gate silicon oxide layer on top of the layer of silicon carbide and the electrodes, and performing a second lift-off operation to fabricate an optically transparent ITO gate between the electrodes.

Formation of field-tunable silicon carbide defect qubits with optically transparent electrodes and silicon oxide surface passivation

A method of: providing an off-axis silicon carbide substrate, and etching the surface of the substrate with a dry gas, hydrogen, or an inert gas.

Reduction of basal plane dislocations in epitaxial SiC using an in-situ etch process

A method of: providing an off-axis 4H&#x2014;SiC substrate, and etching the surface of the substrate with hydrogen or an inert gas.

A plasmon-enhanced terahertz graphene-based photodetector exhibits an increased absorption efficiency attained by utilizing a tunable plasmonic resonance in sub-wavelengths graphene micro-ribbons formed on SiC substrate in contact with an array of bi-metallic electrode lines. The orientation of the graphene micro-ribbons is tailored with respect to the array of sub-wavelengths bi-metallic electrode lines. The graphene micro-ribbons extend at the angle of approximately 45 degrees with respect to the electrode lines in the bi-metal electrodes array. The plasmonic mode is efficiently excited by an incident wave polarized perpendicular to the electrode lines, and/or to the graphene micro-ribbons. The absorption of radiation by graphene is enhanced through tunable geometric parameters (such as, for example, the width of the graphene micro-ribbons) and control of a carrier density in graphene achieved through tuning the gate voltage applied to the photodetector.

Plasmon-enhanced terahertz graphene-based photodetector and method of fabrication

An appropriately configured pulsed laser is focused onto a graphene sheet and is used to form a desired pattern in the graphene. When the laser pulse strikes the graphene, it modifies the bonding state of the carbon atoms in the graphene lattice, acting as a 'blade' and causing a separation in the graphene sheet at the site of the laser pulse without causing damage to the surrounding graphene. The width of the separation, or 'cut' in the graphene sheet can be controlled by controlling characteristics of the laser pulse such as beam shape, beam intensity, pulse width, repetition rate, and wavelength to produce a graphene material having desired electrical, optical, thermal, and/or mechanical properties.

Sub-micron laser patterning of graphene and 2D materials

A method for reducing/eliminating basal plane dislocations from SiC epilayers is disclosed. An article having: an off-axis SiC substrate having an off-axis angle of no more than 6&#xb0;; and a SiC epitaxial layer grown on the substrate. The epitaxial layer has no more than 2 basal plane dislocations per cmat the surface of the epitaxial layer. A method of growing an epitaxial SiC layer on an off-axis SiC substrate by: flowing a silicon source gas, a carbon source gas, and a carrier gas into a growth chamber under growth conditions to epitaxially grow SiC on the substrate in the growth chamber. The substrate has an off-axis angle of no more than 6&#xb0;. The growth conditions include: a growth temperature of 1530-1650&#xb0; C.; a pressure of 50-125 mbar; a C/H gas flow ratio of 9.38&#xd7;10-1.5&#xd7;10; a C/Si ratio of 0.5-3; a carbon source gas flow rate during ramp to growth temperature from 0 to 15 sccm; and an electron or hole concentration of 10-10/cm.

Reduction of basal plane dislocations in epitaxial SiC

Processes for preparation of an epitaxial graphene surface to make it suitable for deposition of high-&#x3ba; oxide-based dielectric compounds such as AlO, HfO, TaO, or TiOare provided. A first process combines ex situ wet chemistry conditioning of an epitaxially grown graphene sample with an in situ pulsing sequence in the ALD reactor. A second process combines ex situ dry chemistry conditioning of the epitaxially grown graphene sample with the in situ pulsing sequence.

Epitaxial graphene surface preparation for atomic layer deposition of dielectrics

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Alexandria, VA, United States of America

David Kurt Gaskill