Explanipedia

High-Sensitivity Hybrid Photodetection Using Graphene-Based Charge-Coupled Sensors. Open

Stephen W. Howell, Isaac Ruiz, Michael Goldflam, Paul Davids, Richard K. Harrison , et al. · 2023

Graphene-Based Charge-Coupled Devices for Sensitive Optical Detection. Open

Stephen W. Howell, Thomas Edwin Beechem, Paul Davids, Michael Goldflam, Richard K. Harrison , et al. · 2023

Tunable infrared pixels having unpatterned graphene layer and conductive metasurface Open

III Beechem, Michael Goldflam, Anna Tauke‐Pedretti, Isaac Ruiz, David W. Peters , et al. · 2023

A monolithically integrated, tunable infrared pixel comprises a combined broadband detector and graphene-enabled tunable metasurface filter that operate as a single solid-state device with no moving parts. Functionally, tunability results …

Radiation detector using a graphene amplifier layer Open

Stephen W. Howell, David W. Peters, III Beechem, Isaac Ruiz, Richard K. Harrison , et al. · 2023

A radiation field is detected or imaged using one or more junction devices in which a two-dimensional conductor layer is capacitively coupled to a semiconductor absorber layer. In the junction devices, pixel-level amplification and read-ou…

Electrochemical assembly of organic molecules by the reduction of iodonium salts Open

Shawn M. Dirk, Stephen W. Howell, David R. Wheeler · 2023

Methods are described for the electrochemical assembly of organic molecules on silicon, or other conducting or semiconducting substrates, using iodonium salt precursors. Iodonium molecules do not assemble on conducting surfaces without a n…

Sub-wavelength antenna enhanced bilayer graphene tunable photodetector Open

III Beechem, Stephen W. Howell, David W. Peters, Paul Davids, Taisuke Ohta · 2023

The integration of bilayer graphene with an absorption enhancing sub-wavelength antenna provides an infrared photodetector capable of real-time spectral tuning without filters at nanosecond timescales.

Tunable graphene-based infrared reflectance filter having patterned nanoantenna layer and unpatterned graphene layer Open

III Beechem, Michael Goldflam, Stephen W. Howell, David W. Peters, Isaac Ruiz , et al. · 2023

An actively tunable optical filter can control the amplitude of reflected infrared light. The filter exploits the dependence of the excitation energy of plasmons in a continuous and unpatterned sheet of graphene, on the Fermi-level, which …

Tripartite Correlations in Quantum Radar and Communication Systems Open

Rory A. Bowell, Matthew J. Brandsema, Ram M. Narayanan, Stephen W. Howell, Jonathan M. Dilger · 2023

Quantum-based systems are an emerging topic of research due to their potential for increasing performance in a variety of classical systems.In radar and communication systems, quantum technologies have been explored in an effort to increas…

Detection of high energy ionizing radiation using deeply depleted graphene–oxide–semiconductor junctions Open

Isaac Ruiz, György Vizkelethy, Anthony E. McDonald, Stephen W. Howell, Paul Thelen , et al. · 2022

Graphene’s linear band structure and two-dimensional density of states provide an implicit advantage for sensing charge. Here, these advantages are leveraged in a deeply depleted graphene–oxide–semiconductor (D2GOS) junction detector archi…

Detection of High Energy Ionizing Radiation using Deeply Depleted Graphene-Oxide-Semiconductor Junctions Open

Isaac Ruiz, György Vizkelethy, Anthony E. McDonald, Stephen W. Howell, Paul Thelen , et al. · 2022

Graphene's linear bandstructure and two-dimensional density of states provide an implicit advantage for sensing charge. Here, these advantages are leveraged in a deeply depleted graphene-oxide-semiconductor (D2GOS) junction detector archit…

COMPARISON OF CORRELATION PERFORMANCE FOR VARIOUS MEASUREMENT SCHEMES IN QUANTUM BIPARTITE RADAR AND COMMUNICATION SYSTEMS Open

Rory A. Bowell, Matthew J. Brandsema, Ram M. Narayanan, Stephen W. Howell, Jonathan M. Dilger · 2022

Bipartite systems have become popular in emerging quantum radar and quantum communication systems.This paper analyzes the various correlation coefficients for different types of quantum radar measurement schemes, such as: (i) immediate det…

An open-endcap blade trap for radial-2D ion crystals Open

Yuanheng Xie, Jiafeng Cui, Marissa D’Onofrio, A. J. Rasmusson, Stephen W. Howell , et al. · 2021

We present the design and experimental demonstration of an open-endcap radio frequency trap to confine ion crystals in the radial-two dimensional (2D) structural phase. The central axis of the trap is kept free of obstructions to allow for…

Growth and Modification of Graphene: An Overview of Graphene (Opto)Electronics R&D at Sandia. Open

Chi Chiu Chan, Taisuke Ohta, Iii Beechem, Stephen W. Howell, David R. Wheeler , et al. · 2020

Graphene Integration: Film Synthesis and Device Fabrication. Open

Isaac Ruiz, Stephen W. Howell, Michael Goldflam, Joel R. Wendt · 2020

Interface Defect Engineering for Improved Graphene-Oxide-Semiconductor Junction Photodetectors Open

Isaac Ruiz, Thomas E. Beechem, Sean W. Smith, Peter Dickens, Elizabeth A. Paisley , et al. · 2019

The deeply depleted graphene-oxide-semiconductor (D²GOS) junction detector provides an effective architecture for photodetection, enabling direct readout of photogenerated charge. Because of an inherent gain mechanism proportion…

The deeply depleted graphene-insulator-semiconductor junction: a versatile approach towards light sensing across the electromagnetic spectrum (Conference Presentation) Open

Isaac Ruiz, Michael Goldflam, Thomas E. Beechem, Stephen W. Howell · 2019

The deeply depleted graphene-insulator-semiconductor (D2GOS) junction has been shown to be a promising device structure for photon detection, due to its high responsivity, signal to noise ratio and ability for direct readout of individual …

Depleted Graphene-Oxide-Semiconductor Junctions for High Energy Radiation Detection Open

Isaac Ruiz, Thomas E. Beechem, György Vizkelethy, Paul Thelen, Joshua Shank , et al. · 2019

The deeply depleted graphene-oxide-semiconductor junction (D ² GOS) architecture has been shown to be a highly sensitive light detector [1]. In this architecture, photogenerated charge in the depletion region of the semiconducto…

Passivation of Graphene Films and Their Visibility. Open

Isaac Ruiz, Michael Goldflam, Stephen W. Howell, Anthony E. McDonald, B.L. Draper · 2019

Tunable TaxN Josephson Junctions for Scalable High Performance Low Power Computing. Open

Michael David Henry, Rupert Lewis, Stephen W. Howell, Steven L. Wolfley, Lyle Brunke , et al. · 2019

Tunable Infrared Pixels via Monolithically Integrated Dynamic Graphene Metasurfaces Open

Thomas E. Beechem, Michael Goldflam, Isaac Ruiz, Stephen W. Howell, Michael B. Sinclair , et al. · 2019

Integrating Resonant Structures with IR Detectors. Open

Michael Goldflam, Michael Goldflam, Evan Michael Anderson, Evan Michael Anderson, Salvatore Campione , et al. · 2018

Infrared Nanoantenna-Coupled Rectenna for Energy Harvesting. Open

Joshua Shank, Paul Davids, David W. Peters, Stephen W. Howell, Emil Kadlec · 2018

Reflectance modulation from a metasurface coupled to intersubband transitions in semiconductor quantum wells using quantum tunneling (Conference Presentation) Open

Raktim Sarma, Salvatore Campione, Michael Goldflam, Loan T. Le, M. D. Lange , et al. · 2018

Coupling of metasurfaces to intersubband transitions (ISTs) in semiconductor quantum wells (QWs) has been extensively studied for various applications ranging from generating giant nonlinear optical response to designing tunable metasurfac…

Tunable Perfect Absorption. Open

Michael Goldflam, Stephen W. Howell, Isaac Ruiz, David W. Peters · 2018

Tunable dual-band graphene-based infrared reflectance filter Open

Michael Goldflam, Isaac Ruiz, Stephen W. Howell, Joel R. Wendt, Michael B. Sinclair , et al. · 2018

We experimentally demonstrated an actively tunable optical filter that controls the amplitude of reflected long-wave-infrared light in two separate spectral regions concurrently. Our device exploits the dependence of the excitation energy …

Tunable Nitride Josephson Junctions. Open

Nancy A. Missert, Michael David Henry, Rupert Lewis, Stephen W. Howell, Steven L. Wolfley , et al. · 2017

We have developed an ambient temperature, SiO₂/Si wafer - scale process for Josephson junctions based on Nb electrodes and Ta x N barriers with tunable electronic properties. The films are fabricated by magnetron sputtering. The…

Graphene-Insulator-Semiconductor Junction for Hybrid Photodetection Modalities Open

Stephen W. Howell, Isaac Ruiz, Paul Davids, Richard K. Harrison, Sean W. Smith , et al. · 2017

Optical Contrast of Passivated Graphene Films. Open

Isaac Ruiz, Stephen W. Howell, B.L. Draper, Michael Goldflam · 2017

Dual-band tunable graphene-based filter Open

Michael Goldflam, Isaac Ruiz, Stephen W. Howell, Thomas E. Beechem · 2017

We have demonstrated a scalable dual-band tunable infrared filter based on gating of a continuous graphene layer. The measured and modeled response of the device are in good agreement.

Vacuum radiometry of an infrared nanoantenna-coupled tunnel diode rectenna Open

Paul Davids, Emil Kadlec, Joshua Shank, David W. Peters, Stephen W. Howell · 2017

We examine the vacuum infrared photoresponse of a large-area nanoantenna-coupled tunnel diode rectenna resulting from thermal radiation from a temperature controlled heater. The measured infrared photocurrent is obtained as a function of t…

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