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Search Publications by: Randolph Elmquist (Fed)

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Displaying 51 - 75 of 137

Transport of NIST Graphene Quantized Hall Devices and Comparison with AIST Gallium-Arsenide Quantized Hall Devices

July 9, 2018
Author(s)
Dean G. Jarrett, Takehiko Oe, Randolph E. Elmquist, Nobu Kaneko, Albert F. Rigosi, Bi Y. Wu, Hsin Y. Lee, Yanfei Yang
We report the results of a pilot study where two graphene quantized Hall resistance (QHR) devices made at the National Institute of Standards and Technology (NIST) were hand carried from the USA to the National Institute for Advanced Industrial Science and

A Table-Top Graphene Quantized Hall Standard

July 8, 2018
Author(s)
Albert F. Rigosi, Alireza R. Panna, Shamith U. Payagala, George R. Jones Jr., Marlin E. Kraft, Mattias Kruskopf, Bi Y. Wu, Hsin Y. Lee, Yanfei Yang, Dean G. Jarrett, Randolph E. Elmquist, David B. Newell
We report the performance of a quantum standard based on epitaxial graphene maintained in a 5 T table-top cryocooler system. The ν = 2 resistance plateau, with a value of RK-90/2, is used to scale to 1 kΩ, allowing comparisons of the performance of a

Uncertainty of the Ohm Using Cryogenic and Non-Cryogenic Bridges

July 8, 2018
Author(s)
Alireza Panna, Marlin E. Kraft, Albert Rigosi, George R. Jones Jr., Shamith Payagala, Mattias Kruskopf, Dean G. Jarrett, Randolph Elmquist
We describe recent scaling measurements to decade resistance levels based on both cryogenic and non-cryogenic current comparator bridges. National measurement institutes and the International Bureau of Weights and Measures derive traceability for the SI

Examining epitaxial graphene surface conductivity and quantum Hall device stability with Parylene passivation

March 20, 2018
Author(s)
Albert F. Rigosi, Chieh-I Liu, Bi Y. Wu, Hsin Y. Lee, Mattias Kruskopf, Yanfei Yang, Heather M. Hill, Jiuning Hu, Emily G. Bittle, Jan Obrzut, Angela R. Hight Walker, Randolph E. Elmquist, David B. Newell
When it comes to the advancement of quantized Hall resistance (QHR) standards, homogeneous, single-crystal, monolayer epitaxial graphene (EG) is the most promising candidate. EG-based quantum Hall devices, though emerging as a useful tool for metrology

Measuring the dielectric and optical response of millimeter-scale amorphous and hexagonal boron nitride films grown on epitaxial graphene

December 1, 2017
Author(s)
Albert F. Rigosi, Heather M. Hill, Nicholas R. Glavin, Sujitra J. Pookpanratana, Yanfei Yang, Alexander G. Boosalis, Jiuning Hu, Anthony Rice, Andrew A. Allerman, Nhan V. Nguyen, Christina A. Hacker, Randolph E. Elmquist, Angela R. Hight Walker, David B. Newell
Monolayer epitaxial graphene (EG), grown on the Si face of SiC, is an advantageous material for a variety of electronic and optical applications. EG forms as a single crystal over millimeter- scale areas and consequently, the large scale single crystal can

Probing the dielectric response of the interfacial buffer layer in epitaxial graphene via optical spectroscopy

November 28, 2017
Author(s)
Heather M. Hill, Albert Rigosi, Sugata Chowdhury, Yanfei Yang, Nhan Van Nguyen, Francesca Tavazza, Randolph Elmquist, David B. Newell, Angela R. Hight Walker
Monolayer epitaxial graphene (EG) is a suitable candidate for a variety of electronic applications. One advantage of EG growth on the Si face of SiC is that it develops as a single crystal, as does the layer below, referred to as the interfacial buffer

Electrical stabilization of surface resistivity in epitaxial graphene systems by amorphous boron nitride encapsulation

May 25, 2017
Author(s)
Albert F. Rigosi, Chieh-I Liu, Nicholas R. Glavin, Yanfei Yang, Heather M. Hill, Jiuning Hu, Angela R. Hight Walker, Curt A. Richter, Randolph E. Elmquist, David B. Newell
Homogeneous monolayer epitaxial graphene (EG) is an ideal candidate for the development of millimeter-sized devices with single-crystal domains. A clean fabrication process was used to produce EG-based devices with n-type doping level of order 10^12 cm^-2

Preservation of surface conductivity and dielectric loss tangent in large-scale, encapsulated epitaxial graphene measured by non-contact microwave cavity perturbations

May 19, 2017
Author(s)
Albert F. Rigosi, Nicholas R. Glavin, Chieh-I Liu, Yanfei Yang, Jan Obrzut, Heather M. Hill, Jiuning Hu, Hsin Y. Lee, Angela R. Hight Walker, Curt A. Richter, Randolph E. Elmquist, David B. Newell
Regarding the improvement of current quantized Hall resistance (QHR) standards, one promising avenue is the growth of homogeneous monolayer epitaxial graphene (EG). A clean and simple process was used to produce large, precise areas of EG. Properties like

Epitaxial graphene homogeneity and quantum Hall effect in millimeter-scale devices

April 1, 2017
Author(s)
Yanfei Yang, Guangjun Cheng, Chiashain Chuang, Angela R. Hight Walker, Randolph E. Elmquist, Irene G. Calizo, Randall M. Feenstra, Patrick Mende
Quantized magnetotransport is observed in 5.6 × 5.6 mm2 epitaxial graphene devices, grown using highly constrained sublimation on the Si-face of SiC(0001) at high temperature (1900 °C). The precise quantized Hall resistance of Rxy = h/〖2e〗^2 is maintained

Temperature dependence of electron density and electron-electron interactions in monolayer epitaxial graphene grown on SiC

January 25, 2017
Author(s)
Chieh W. Liu, Chiashain Chuang, Yanfei Yang, Randolph Elmquist, Yi-Ju Ho, Hsin Y. Lee, Chi-Te Liang
We report carrier density measurements and electron-electron (e-e) interactions in monolayer epitaxial graphene grown on SiC. The temperature (T)-independent carrier density determined from the Shubnikov-de Haas (SdH) oscillations clearly demonstrates that

Insulator-quantum Hall transition in monolayer epitaxial graphene

July 22, 2016
Author(s)
Lung-I Huang, Yanfei Yang, Randolph Elmquist, Shun-Tsung Lo, Fan-Hung H. Liu, Chi-Te Laing
We report on magneto-transport measurements on low-density, large-area monolayer epitaxial graphene devices grown on SiC. We observe temperature (T)-independent crossing points in the longitudinal resistivity (rho)sub(xx), which are signatures of the

Quantum Hall Resistance Traceability for the NIST-4 Watt Balance

July 10, 2016
Author(s)
Dean G. Jarrett, Randolph Elmquist, Marlin E. Kraft, George R. Jones Jr., Shamith Payagala, Frank Seifert, Stephan Schlamminger, Darine El Haddad
Scaling from the quantum Hall resistance to 100 Ω standard resistors used by the NIST-4 Watt Balance involves multiple resistance standards and bridges to provide the lowest possible uncertainty. Described here is the infrastructure and procedures

Surface conductance of graphene from non-contact resonant cavity

March 15, 2016
Author(s)
Jan Obrzut, Caglar Dogu Emiroglu, Oleg A. Kirillov, Yanfei Yang, Randolph E. Elmquist
A method is established to reliably determine surface conductance of single-layer or multi-layer atomically thin nano-carbon graphene structures. These can be synthesized by chemical vapor deposition (CVD), epitaxial growth on silicon carbide (SiC)

Low-Ohmic Resistance Comparison: Measurement Capabilities and Resistor Traveling Behavior

March 1, 2016
Author(s)
Marlin E. Kraft, Randolph E. Elmquist, Gert Rietveld, Jan van der Beek, Alessandro Mortara, Beat Jeckelmann
The low-ohmic resistance measurement capabilities of the Van Swinden Laboratorium, National Institute of Standards and Technology, and the Federal Office of Metrology (METAS) were compared using a set of resistors with values 100 mΩ, 10 mΩ, 1 mΩ, and 100

Reference Module in Materials Science and Materials Engineering MATS 01908

February 1, 2016
Author(s)
Randolph E. Elmquist, Anthony Hartland
The cryogenic current comparator is used to maintain national representations of the ohm based on the quantized Hall resistance standard. The measurement technique utilizes the Meissner effect to establish accurate resistance ratios with specialized

Quantized Hall resistance in large-scale monolayer graphene

November 28, 2015
Author(s)
Yanfei Yang, Chiashain Chuang, Chieh W. Liu, Randolph Elmquist
Abstract: Graphene is an atomic-thickness carbon lattice that can be exfoliated from solid graphite or grown using high temperature processing methods on a variety of substrates. Many practical applications of large-area graphene, however, are limited by

Transportation Effect and Basic Characteristics of Ni-Cr Based Metal-Foil Standard Resistors Examined in a Trilateral Comparison Pilot Study between KRISS, NIST and NMIJ

June 1, 2015
Author(s)
Marlin E. Kraft, Randolph E. Elmquist, Nobu-hisa Kaneko, Wan-Seop Kim, Dong Hun Chae, Takehiko Oe
The transportation effect and other important characteristics of 100-Ω standard resistors of a new construction have been studied. For transportation effect, four resistors have been transported by air between three national metrology institutes: the Korea

Development of Low Carrier Density Graphene Devices

August 1, 2014
Author(s)
Yanfei Yang, Lung-I Huang, David B. Newell, Yasuhiro Fukuyama, Mariano A. Real, Randolph Elmquist
Epitaxial graphene on SiC(0001) is used to fabricate Hall bar structures for metrological applications with a fabrication process that has been developed to eliminate organic chemical contamination of the graphene. Before any lithographic patterning a

Transportation Effect of the Ni-Cr Based Metal-Foil Standard Resistors in the Trilateral Comparison Pilot Study between KRISS, NIST and NMIJ

August 1, 2014
Author(s)
Randolph E. Elmquist, Nobu-hisa Kaneko, Takehiko Oe, Wan-Seop Kim, Dong Hun Chae, Marlin E. Kraft
This paper describes a study on the transportation effect using four 100 Ω standard resistors of a new construction. All resistors have been transported by air: two of the resistors in hand-carried luggage and the other two by normal air freight. The

Low carrier density epitaxial graphene devices on SiC

June 1, 2014
Author(s)
Yanfei Yang, Lung-I Huang, Yasuhiro Fukuyama, Fan-Hung Liu, Mariano Real, Paola Barbara, Chi-Te Liang, David B. Newell, Randolph Elmquist
Monolayer epitaxial graphene grown on a hexagonal silicon carbide (SiC) substrate is typically found to be heavily n-doped (10e13 cm-2) and in most devices made with the as-grown epitaxial graphene the quantized Hall resistance plateau with Landau level

Localization and electron-electron interactions in few-layer epitaxial graphene

May 28, 2014
Author(s)
Randolph E. Elmquist, Fan-Hung Liu, Lung-I Huang, Yasuhiro Fukuyama, Chi-Te Liang, Yanfei Yang
We study the quantum corrections caused by electron-electron (e-e) interactions and localization to the conductivity in few-layer epitaxial graphene, in which the carriers responsible for transport are massive. Our results demonstrate that the diffusive

Precision high-value resistance scaling with a two-terminal cryogenic current comparator

March 1, 2014
Author(s)
Randolph E. Elmquist, George R. Jones, Felipe L. Hernandez-Marquez, Marcos Bierzychudek
We describe a cryogenic two-terminal high-resistance bridge and its application in precision resistance scaling from the quantized Hall resistance (QHR) at RH = RK/2 = 12 906.4035 _ to decade resistance standards with values between 1 M_ and 1 G_. The