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Search Publications

NIST Authors in Bold

Displaying 76 - 100 of 716

Targeted enrichment of 28Si thin films for quantum computing

March 9, 2020
Author(s)
Ke Tang, Hyun S. Kim, Aruna N. Ramanayaka, David S. Simons, Joshua M. Pomeroy
We report on the growth of isotopically enriched 28Si epitaxial films with precisely controlled enrichment levels, ranging from natural abundance ratio of 92.2% all the way to 99.99987 % (0.832 × 10-6 mol/mol 29Si). Isotopically enriched 28Si is regarded

Carrier mobility of silicon by sub-bandgap time-resolved terahertz spectroscopy

February 26, 2020
Author(s)
Timothy J. Magnanelli, Edwin J. Heilweil
Low density charge mobility from below bandgap, two-photon photoexcitation of bulk Silicon (Si) is interrogated using time-resolved terahertz spectroscopy (TRTS). Total charge mobility is measured as a function of excitation frequency and fluence (charge

Use of quantum effects as potential qualifying metrics for "quantum grade silicon"

December 30, 2019
Author(s)
Aruna N. Ramanayaka, Ke Tang, Joseph A. Hagmann, Hyun S. Kim, David S. Simons, Curt A. Richter, Joshua M. Pomeroy
Across solid state quantum information, material deficiencies limit performance through enhanced relaxation, charge defect motion, or isotopic spin noise. While classical measurements of device performance provide cursory guidance, specific qualifying

Appraising the extensibility of optics-based metrology for emerging materials

October 4, 2019
Author(s)
Bryan M. Barnes, Mark-Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
To advance computational capabilities beyond conventional scaling limitations, novel device architectures enabled by emerging materials may be required. Optics-based methodologies, central to modern-day process control, will be pursued by the

Automated Mechanical Exfoliation of MoS2 and MoTe2 Layers for 2D Materials Applications

September 13, 2019
Author(s)
Albert Davydov, Sergiy Krylyuk, Kyle J. DiCamillo, Makarand Paranjape, Wendy Shi
An automated technique is presented for mechanically exfoliating single-layer and few-layer transition metal dichalcogenides using controlled shear and normal forces imposed by a parallel plate rheometer. A thin sample that is removed from bulk MoS2 or

A compact, UHV ion source for enriching 28Si and depositing epitaxial thin films

August 22, 2019
Author(s)
Ke Tang, Hyun S. Kim, Aruna N. Ramanayaka, David S. Simons, Joshua M. Pomeroy
An ultra-high-vacuum (UHV) compatible Penning ion source for growing pure, highly enriched 28Si epitaxial thin films is presented. Enriched 28Si is a critical material for quantum information due to the elimination of nuclear spins and, in some cases, must

Streaming Batch Eigenupdates for Hardware Neural Networks

August 6, 2019
Author(s)
Brian D. Hoskins, Matthew W. Daniels, Siyuan Huang, Advait Madhavan, Gina C. Adam, Nikolai B. Zhitenev, Jabez J. McClelland, Mark D. Stiles
Neuromorphic networks based on nanodevices, such as metal oxide memristors, phase change memories, and flash memory cells, have generated considerable interest for their increased energy efficiency and density in comparison to graphics processing units

Materials Science in the AI age: high-throughput library generation, machine learning and a pathway from correlations to the underpinning physics

July 22, 2019
Author(s)
Kamal Choudhary, Aaron G. Kusne, Francesca M. Tavazza, Jason R. Hattrick-Simpers, Rama K. Vasudevan, Apurva Mehta, Ryan Smith, Lukas Vlcek, Sergei V. Kalinin, Maxim Ziatdinov
The use of advanced data analytics, statistical and machine learning approaches (‘AI’) to materials science has experienced a renaissance, driven by advances in computer sciences, availability and access of software and hardware, and a growing realization

Electron Reflectometry for Measuring Nanostructures on Opaque Substrate

July 8, 2019
Author(s)
Lawrence H. Friedman, Wen-Li Wu
Here, we present a method for measuring dimensions of nanostructures using specular reflection of electrons from an opaque surface. Development of this method has been motivated by measurement needs of the semiconductor industry, but it can also be more

A Truth-Matrix View into Unary Computing

June 22, 2019
Author(s)
Advait Madhavan, Georgios Tzimpragos, Mark D. Stiles, Timothy Sherwood
Our community has been exploring Time-of-arrival based codes as a candidate for very low energy information processing. A ``space-time'' algebra has been recently proposed that captures the essential features of such a paradigm. In order to gain some

Electronics Supply Chain Integrity Enabled by Blockchain

June 1, 2019
Author(s)
Xiaolin Xu, Fahim Rahman, Bicky Shakya, Apostol Vassilev, Domenic Forte, Mark Tehranipoor
Electronic systems are ubiquitous today, playing an irreplaceable role in our personal lives as well as in critical infrastructures such as power grid, satellite communication, and public transportation. In the past few decades, the security of software

Induced quantum dot probe for materials characterization

April 19, 2019
Author(s)
Hilary M. Hurst, Yun-Pil Shim, Rusko Ruskov, Charles Tahan
We propose a non-destructive means of characterizing a semiconductor wafer via measuring parameters of an induced quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single

Reproducible Performance Improvements to Monolayer MoS2 Transistors through Exposed Material Forming Gas Annealing

April 16, 2019
Author(s)
Nicholas B. Guros, Son T. Le, Siyuan Zhang, Brent A. Sperling, Jeffery B. Klauda, Curt A. Richter, Arvind Balijepalli
We have developed an optimized process to realize high-performance field-effect transistor (FET) arrays from large-area 2D MoS2 films with an average yield of 85 %. A central element of the technique is a new exposed film forming gas anneal (EF- FGA) that

Switching variability factors in compliance-free metal oxide RRAM

March 31, 2019
Author(s)
Dmitry Veksler, Gennadi Bersuker, A W. Bushmaker, Pragya Shrestha, Kin P. Cheung, Jason Campbell
Switching variability in polycrystalline compliance-free HfO2-based 1R RRAM is evaluated employing ultra-fast low voltage pulse approach. Changes in filament conductivity are linked to the variations of energy released in a switching process. This study

Low-resistance, high-yield electrical contacts to atom scale Si:P devices using palladium silicide

March 29, 2019
Author(s)
Scott W. Schmucker, Pradeep Namboodiri, Ranjit Kashid, Xiqiao Wang, Binhui Hu, Jonathan Wyrick, Alline Myers, Joshua D. Schumacher, Richard M. Silver, Michael Stewart
Scanning tunneling microscopy (STM) enables the fabrication of 2-D delta-doped structures in Si with atomistic precision, with applications from tunnel field effect transistors to qubits. The combination of a very small contact area and the restrictive

UV LEDs Based on p-i-n Core-Shell AlGaN/GaN Nanowire Heterostructures Grown by N-polar Selective Area Epitaxy

March 20, 2019
Author(s)
Matthew Brubaker, Kristen Genter, Alexana Roshko, Paul T. Blanchard, Bryan T. Spann, Todd E. Harvey, Kris A. Bertness
Ultraviolet light-emitting diodes (UV LEDs) fabricated from N-polar AlGaN/GaN core-shell nanowires with p-i-n structure produced electroluminescence at 365 nm with 5x higher intensities than similar GaN homojunction LEDs. The improved characteristics were

Probe assisted localized doping of aluminum into silicon substrates

February 20, 2019
Author(s)
Jungjoon Ahn, Santiago D. Solares, Lin You, Hanaul Noh, Joseph Kopanski, Yaw S. Obeng
In this paper, we demonstrate AFM probe assisted deterministic doping (PADD) of Al into an n- type Si (100) wafer, to generate nanoscale counter-doped junctions with a few nanometers depth from Si surface. The local electrical potential changes resulting

X-ray Metrology for the Semiconductor Industry Tutorial

February 1, 2019
Author(s)
Daniel F. Sunday, Wen-Li Wu, Scott Barton, Regis J. Kline
The semiconductor industry is in need of new, in-line dimensional metrology methods with higher spatial resolution for characterizing their next generation nanodevices. The purpose of this short course is to train the semiconductor industry on the NIST

MoS2 cleaning by acetone and UV-Ozone: Geological vs. synthetic material (Letter)

January 25, 2019
Author(s)
Keren M. Freedy, Sales G. Maria, Sergiy Krylyuk, Albert Davydov, Stephen J. McDonnell
The effects of poly(methyl methacrylate) PMMA removal procedures on the surface chemistry of both geological and chemical vapor deposited (CVD) MoS2 are investigated. X-ray photoelectron spectroscopy is employed following acetone dissolution, thermal
Displaying 76 - 100 of 716