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Search Publications by: David Gundlach (Fed)

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Displaying 76 - 100 of 180

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

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

Measuring domain sizes and compositional heterogeneities in P3HT-PCBM bulk heterojunction thin films with 1H spin diffusion NMR spectroscopy

March 21, 2012
Author(s)
Ryan C. Nieuwendaal, Hyun Wook Ro, David Germack, Regis J. Kline, Calvin Chan, Amit K. Agrawal, David J. Gundlach, David L. VanderHart, Dean M. DeLongchamp
In this manuscript we show that 1H spin diffusion NMR is a valuable method for estimating the domain sizes in thin films of a polymer-fullerene blend for bulk heterojunction (BHJ) photovoltaics. Variations in common BHJ film processing parameters have

Controlling the Microstructure of Solution-Processible Small Molecules in Thin-Film Transistors through Substrate Chemistry

February 4, 2011
Author(s)
Regis J. Kline, Steven D. Hudson, Xinran Zhang, David J. Gundlach, Andrew Moad, Lee J. Richter, Oana Jurchescu, Thomas Jackson, Sanker Subramanian, John E. Anthony, Michael F. Toney
Solution-processible small molecules have tremendous potential for providing both high charge carrier mobility and low cost processing. This study outlines a detailed microstructural study of the effect of substrate chemistry on fluorinated 5,11-bis

Mapping Crystal Orientation in High Performance Thienothiophene Copolymer Thin Films

December 8, 2010
Author(s)
Xinran Zhang, Steven D. Hudson, Dean M. DeLongchamp, David J. Gundlach, Martin Heeney, Iain McCulloch
Mapping of crystalline grain orientation for solution-processed semiconducting polymer thin films is key to understanding charge transport in electronic devices based on them and yet challenging. In this work, a high mobility thienothiophene copolymer

Characterization of a Soluble Anthradithiophene Derivative

October 1, 2010
Author(s)
Brad Conrad, Calvin Chan, Marsha A. Loth, Sean R. Parkin, Xinran Zhang, John E. Anthony, David J. Gundlach
The structural and electrical properties of a new solution processable material, 2,8-diflouro-5,11-tert-butyldimethylsilylethynl anthradithiophene (TBDMS), were measured for single crystal and spun cast thin-film transistors. TBDMS is observed to readily

Why Contacts Matter

July 7, 2010
Author(s)
David J. Gundlach, Y. Li, D. A. Zhou, D A. Mourey, Thomas Jackson

Compact and Distributed Modeling of Cryogenic Bulk MOSFET Operation

June 1, 2010
Author(s)
Akin Akturk, M. Holloway, S. Potbhare, David J. Gundlach, B Li, Neil Goldsman, M Peckerar, Kin P. Cheung
We have developed compact and physics-based distributed numerical models for cryogenic bulkMOSFET operation down to 20 K to advance simulation and first-pass design of device and circuit operation at low temperatures. To achieve this, we measured and