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Highlights

Feb 28, 2013
UPENN Materials Research Science and Engineering Centers

Topological Semimetal in Tensile Strained HgTe

C.L. Kane, E.J. Mele and A.M. Rappe, University of Pennsylvania

In the past few years, the theory of topological band structures has been generalized beyond topological insulators to include topological semimetals, including Weyl semimetals, Dirac semimetals and other “symmetry protected” topological states.  HgTe is a semimetal in which the degeneracy of the conduction and valence band at the G point is protected by symmetry.  In their early work on topological insulators, Fu and Kane showed that straining HgTe opens a gap at G, resulting in a topological insulator. 
Feb 20, 2013
Northwestern Materials Research Science and Engineering Center

Thermal Stability of Amorphous Zn-In-Sn-O Films Diana

Diana E. Proffit1, Thomas Philippe1, Jonathan D. Emery1, Qing Ma2, D. Bruce Buchholz1, Peter W. Voorhees1, Michael J. Bedzyk1, Robert P.H. Chang1, Thomas O. Mason1

Diana E. Proffit1, Thomas Philippe1, Jonathan D. Emery1, Qing Ma2, D. Bruce Buchholz1, Peter W. Voorhees1, Michael J. Bedzyk1, Robert P.H. Chang1, Thomas O. Mason1 1Northwestern University Materials Research Science & Engineering Center2DND-CAT, Northwestern Synchrotron Research Center at Advanced Photon
Feb 20, 2013
Northwestern Materials Research Science and Engineering Center

A Range of Amorphous Structures

D.B. Buchholz, L. Zeng, M.J. Bedzyk and R.P.H. Chang

A range of amorphous structures for a single chemical-composition material (Indium Oxide) were observed; the structure dependent on the growth conditions. The carrier mobility and film (not carrier) density of the films was dependent on growth temperature. Films grown at 0°C and below are amorphous The film density decreased from 7.0 g/cm3 at 0°C to 5.4 g/cm3 at -100°C; the carrier mobility decrease from ~57 cm2/V•s to ~20 cm2/V•s over this same temperature range. The peak in mobility at 0°C adds to the body
Feb 20, 2013
Northwestern Materials Research Science and Engineering Center

High Performance Carbon Nanotube Thin-Film Transistors Enabled by Hybrid Molecular Dielectrics

Vinod K. Sangwan, Rocio Ponce Ortiz, Justice M. P. Alaboson, Jonathan D. Emery, Michael J. Bedzyk, Lincoln J. Lauhon, Tobin J. Marks, and Mark C. Hersam

Over the past decade, semiconducting carbon nanotube (CNT) thin films have been recognized as contending materials for a wide range of applications in electronics, energy, and sensing. Nevertheless, CNT transistor performance suitable for real-world applications awaits understanding-based progress in the integration of independently pioneered device components. We achieve this here by integrating high-purity semiconducting CNT films with a customdesigned hybrid inorganic-organic gate dielectric.
Jan 30, 2013

Triangle Small Angle X-Ray Scattering Facility

In an effort, spearheaded by Triangle MRSEC, we received support through the NSF-MRI program for the purchase of Small Angle X-Ray Scattering (SAXS) instrumentation. The state-of-the-art instruments will serve the greater Research Triangle community for research and education, and will be housed in Duke's Shared Materials Instrumentation Facility (SMIF).
Jan 19, 2013
Northwestern Materials Research Science and Engineering Center

X-ray Standing Wave Mapping of Graphene/SiC

J. Emery1, B. Detlefs2, H. Karmel1, V. Wheeler3, D.K. Gaskill3, M. Hersam1, J. Zegenhagen2, M. Bedzyk1 1Northwestern University Materials Research Science & Engineering Center 2European Synchrotron Radiation Facility, 3U.S. Naval Research Lab
Jan 17, 2013
UMN Materials Research Science and Engineering Center (2014)

First Observation of Hall Effect in Polymer Transistors

C. Daniel Frisbie (IRG-2) & Chris Leighton (IRG-3)

Printed transistors employing both the bench-mark polymer semiconductor poly(3-hexyl-thiophene) and ultra-high capacitance ion gel gate insulators exhibit unusually large hole mobilities near 1 cm2/Vs at high charge densities (0.2 holes/ring).
Jan 16, 2013
Genetically Engineered Materials Science and Engineering Center (2005)

SAPs: Self Assembled Peptides

Developed in GEMSEC, biocombinatorially selected solid binding peptides with short (7-15) amino acid (AA) sequences can bind to atomically flat materials via molecular recognition that leads to surface diffusion, clustering and long-range ordered assembly commensurate with the underlying crystallographic solid lattice.