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Search Publications by: Curt A. Richter (Fed)

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Displaying 51 - 75 of 238

Fe-catalyzed etching of exfoliated graphite through carbon hydrogenation

January 8, 2016
Author(s)
Guangjun Cheng, Christina A. Hacker, Curt A. Richter, Angela R. Hight Walker
We present an investigation on the etching of graphite catalyzed by the particles produced by dewetting Fe thin films on graphite in forming gas. Raman mapping of the etched graphite shows the thickness variation in the etched channels and reveals that the

Edge-state Transport in Graphene p-n Junctions in the Quantum Hall Regime

December 7, 2015
Author(s)
Nikolai Klimov, Son T. Le, Jun Yan, Pratik Agnihotri, Everett Comfort, Ji Ung Lee, David B. Newell, Curt A. Richter
We experimentally investigate charge carrier transport in a graphene p-n junction device by using independent p-type and n-type electrostatic gating which allow full characterization of the junction interface in the quantum Hall regime covering a wide

Self-Assembled Monolayers Impact Cobalt Interfacial Structure in Nanoelectronic Junctions

March 5, 2015
Author(s)
Sujitra J. Pookpanratana, Leigh Lydecker, Curt A. Richter, Christina A. Hacker
The formation of molecular monolayers on template-stripped cobalt surfaces is reported. The quality of the alkane-based molecular structure was confirmed through spectroscopic measurements. We find that the self-assembly of bifunctional molecules has

Influence of Metal?MoS2 Interface on MoS2 Transistor Performance: Comparison of Ag and Ti Contacts

December 16, 2014
Author(s)
Hui H. Yuan, Guangjun Cheng, Lin You, Haitao Li, Hao Zhu, Wei Li, Joseph J. Kopanski, Yaw S. Obeng, Angela R. Hight Walker, David J. Gundlach, Curt A. Richter, D. E. Ioannou, Qiliang Li
In this work, we present a study of enhancing MoS2 transistor performance by using proper metal contact. We found that the on-state current of MoS2 field-effect transistors with 30 nm Au/ 30 nm Ag contacts is enhanced more than 60 times and the

Polarization of Bi2Te3 Thin Film in a Floating-Gate Capacitor Structure

December 8, 2014
Author(s)
Hui H. Yuan, Kai Zhang, Haitao Li, Hao Zhu, John E. Bonevich, Helmut Baumgart, Curt A. Richter, Qiliang Li
Metal-Oxide-Semiconductor capacitors with Bi2Te3 thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of

Attachment of a Reduction-Oxidative Active Diruthenium Compound to Au and Si Surfaces by “Click” Chemistry

August 10, 2014
Author(s)
Sujitra J. Pookpanratana, Joseph W. Robertson, Curt A. Richter, Christina A. Hacker, Lee J. Richter, Julia Savchenko, Steven Cummings, Tong Ren
We report the formation of molecular monolayers containing redox-active diruthenium(II,III) compound to gold and silicon surfaces via “click” chemistry. The use of Cu-catalyzed azide-alkyne cycloaddition enables modular design of molecular surfaces and

Interface Engineering to Control Magnetic Field Effects of Organic-Based Devices by Using a Molecular Self-Assembled Monolayer

June 26, 2014
Author(s)
Hyuk-Jae Jang, Sujitra J. Pookpanratana, Alyssa N. Brigeman, Regis J. Kline, James I. Basham, David J. Gundlach, Christina A. Hacker, Oleg A. Kirillov, Oana Jurchescu, Curt A. Richter
Organic semiconductors hold immense promise for the development of a wide range of innovative devices with their excellent electronic and manufacturing characteristics. Of particular interest are non-magnetic organic semiconductors that show unusual

Tearing and scrolling of transferred graphene

April 29, 2014
Author(s)
Guangjun Cheng, Brent A. Sperling, James E. Maslar, Curt A. Richter, Angela R. Hight Walker
We present an investigation on tearing and scrolling of the transferred graphene on a Si/SiO2 substrate. Graphene grown by chemical vapor deposition (CVD) is transferred onto a Si/SiO2 substrate using a wet polymer-mediated process. Upon the removal of

Highly reproducible and reliable metal/graphene contact by UV-Ozone treatment

March 17, 2014
Author(s)
Wei Li, Christina A. Hacker, Guangjun Cheng, Angela R. Hight Walker, Curt A. Richter, David J. Gundlach, Yiran Liang, boyuan Tian, Xuelei Liang, Lianmao Peng
Resist residue from the device fabrication process is a significant source of contamination at the metal/graphene contact interface. Ultraviolet Ozone (UVO) treatment is proven here, by X-ray photoelectron spectroscopy (XPS) and Raman measurement, to be an

Topological Insulator Bi2Se3 Nanowire High Performance Field-Effect Transistors

April 30, 2013
Author(s)
Hao Zhu, Curt A. Richter, Erhai Zhao, John E. Bonevich, William A. Kimes, Hyuk-Jae Jang, Hui Yuan, Abbas Arab, Oleg A. Kirillov, James E. Maslar, D. E. Ioannou, Qiliang Li
Topological insulators are unique electronic materials with insulating interiors but robust metallic surfaces. Device applications exploiting their remarkable properties, such as surface conduction of helical Dirac electrons, have so far been hampered by

Graphene as Transparent Electrode for Direct Observation of Hole Photoemission from Silicon to Oxide

March 27, 2013
Author(s)
Rusen Yan, Qin Zhang, Oleg A. Kirillov, Wei Li, James I. Basham, Alexander G. Boosalis, Xuelei X. Liang, Debdeep Jena, Curt A. Richter, Alan C. Seabaugh, David J. Gundlach, Huili G. Xing, Nhan V. Nguyen
The outstanding electrical and optical properties of graphene make it an excellent alternative as a transparent electrode. Here we demonstrate the application of graphene as collector material in internal photoemission (IPE) spectroscopy; enabling the

Charge-Based Capacitance Measurements Circuits for Interface With Atomic Force Microscope Probes

March 25, 2013
Author(s)
Joseph J. Kopanski, Muhammad Y. Afridi, Chong Jiang, Michael Lorek, Timothy Kohler, Curt A. Richter
The charge based capacitance measurement (CBCM) technique is highly sensitive to small capacitances and capable integration of onto an AFM tip, thereby reducing stray and wire capacitance to the bare minimum. The CBCM technique has previous been applied to

ELECTRICAL AND PHYSICAL CHARACTERIZATION OF BILAYER CARBOXYLIC ACID FUNCTIONALIZED MOLECULAR LAYERS

January 30, 2013
Author(s)
Sujitra J. Pookpanratana, Joseph W. Robertson, Cherno Jaye, Daniel A. Fischer, Curt A. Richter, Christina A. Hacker
We have used Flip Chip Lamination (FCL) to form monolayer and bilayer molecular junctions of carboxylic acid-containing molecules with Cu atom incorporation. Carboxylic acid-terminated monolayers are self-assembled onto ultrasmooth Au using thiol chemistry

A Unique Photoemission Method to Measure Semiconductor Heterojunction Band Offsets

January 2, 2013
Author(s)
Qin Zhang, Rui Li, Rusen Yan, Thomas Kosel, Grace Xing, Alan Seabaugh, Kun Xu, Oleg A. Kirillov, David J. Gundlach, Curt A. Richter, Nhan V. Nguyen
We report a unique way to measure the energy band offset of a heterojunction by exploiting the light absorption profile in the heterojunction under visible-ultraviolet internal photoemission. This method was used to successfully determine the band

Direct Measurement of Intrinsic Dirac Point and Fermi level at Graphene/Oxide interface and Its Band Alignment by Cavity Enhanced Internal Photoemission

December 17, 2012
Author(s)
Kun Xu, Caifu Zeng, Qin Zhang, Rusen Yan, Peide Ye, Kang Wang, Alan C. Seabaugh, Huili G. Xing, John S. Suehle, Curt A. Richter, David J. Gundlach, Nhan V. Nguyen
We report the first direct measurement of the Dirac point, the Fermi level, and the work function of graphene by performing internal photoemission measurements on a graphene/SiO2/Si structure with a unique optical-cavity enhanced test structure. A complete

Self-aligned multi-channel silicon nanowire field-effect transistors

December 12, 2012
Author(s)
Hao Zhu, Qiliang Li, Hui Yuan, Helmut Baumgart, D. E. Ioannou, Curt A. Richter
Si nanowire field effect transistors (SiNW FETs) with multiple nanowire channels and different gate lengths have been fabricated by using a directed assembly approach combined with standard photolithographic process. The electrical characteristics of SiNW

Observation of spin-valve effect in Alq3 using a low work function metal

September 7, 2012
Author(s)
Hyuk-Jae Jang, Kurt Pernstich, David J. Gundlach, Oana Jurchescu, Curt A. Richter
We present the observation of magnetoresistance in Co/Ca/Alq3/Ca/NiFe spin-valve devices. Thin Ca layers contacting 150 nm thick Alq3 enable the injection of spin-polarized electrons into Alq3 due to engineering of the band alignment. The devices exhibit

Determination of graphene work function and graphene-insulator-semiconductor band alignment by internal photoemission spectroscopy

July 11, 2012
Author(s)
Rusen Yan, Qin Zhang, Wei Li, Irene G. Calizo, Tian T. Shen, Curt A. Richter, Angela R. Hight Walker, Xuelei X. Liang, David J. Gundlach, Nhan Van Nguyen, Huili G. Xing, Alan Seabaugh
We determined the band alignment of a graphene-oxide-silicon structure using internal photoemission spectroscopy. From the flatband voltage and Dirac voltage we infer a 4.3 10e11 cm-2 negative extrinsic charge present on the graphene surface. Also, we