2014 AVS Prairie Chapter Symposium
2
Welcome!
Welcome to Loyola University Chicago and the sunny shores of Lake Michigan. We’re glad that
you could join us for the 2014 AVS Prairie Chapter Symposium, which brings together speakers
from six different institutions, presentations from an additional five, and excellent companies who
have been serving the community for many decades.
We are very excited about the ensemble of presentations at the symposium. The collections of
research, ranging from instrument development and optimization, to spectroscopy, to materials
synthesis, to application in biological systems, is consistent with the mission of the AVS and
represents the highest caliber of science carried out in the area. Most importantly though, it is our
sincerest hope that the research is of the utmost interest to you, the attendee, and broadens your
perspective of the wonderful science being conducted relevant to the AVS mission.
We would like to thank the AVS and our exhibitors; without their support, the event could not have
happened. In addition to financial support, the exhibitors also offer their knowledge and expertise,
and are available to answer questions at the meeting. We also thank the Department of Chemistry
& Biochemistry at Loyola for their support of the symposium. Finally, a special thanks to the many
volunteers from Loyola, who I’m sure you have already encountered, who are ensuring a pleasant
experience for all.
Thank you for attending, and please enjoy the science and our hospitality.
Sincerely,
Jacob Ciszek & Dan Killelea
2014 Prairie Chapter Organizers
2014 AVS Prairie Chapter Symposium
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2014 AVS Prairie Chapter Executive Committee
Advancing the Science and Technology of Materials, Interfaces, and Processing
Chair
Michael Trenary; University of Illinois at Chicago
Vice-Chair
David Czaplewski; Argonne National Laboratory
Treasurer
Julio Soares; University of Illinois at Urbana–Champaign
Secretary
Jessica McChesney; Argonne National Laboratory
Past Chair
Jerry Moore; MassThink
Committee Members:
Yip-Wah Chung; Northwestern University
Scott Dix; Vacuum One
Dan Killelea; Loyola University Chicago
Eric Larson; Midwest Vacuum
Paul Lyman; University of Wisconsin – Milwaukee
Chris McCarthy; Oerlikon Leybold Vacuum
Robert Campbell; Norlux
Richard Rosenberg; Argonne National Laboratory
Allan Rowe; Fermi National Accelerator Laboratory
Jeff Terry; Illinois Institute of Technology
2014 AVS Prairie Chapter Symposium
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Exhibitors at the symposium
We appreciate support from our exhibitors as well as The Department of
Chemistry & Biochemistry at Loyola University Chicago.
Special thanks to Scott Dix and Jeremy Perney for organizing the exhibitors.
2014 AVS Prairie Chapter Symposium
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WiFi Registration Instructions
WiFi Guest Access to Loyola’s Network
User Name:
AVSPrairie
Password:
luc524823
Please see the registration desk if you have any questions regarding access to the Symposium WiFi.
2014 AVS Prairie Chapter Symposium
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2014 AVS Prairie Chapter Symposium
Loyola University Chicago
Schedule
8:15
Registration and Breakfast. Damen Student Center 2nd Floor Atrium
All talks will be in MPR North
8:55
Opening and welcome: Jacob Ciszek, Loyola
Session 1: Moderator, Dan Batzel, Loyola
9:00 Jiaxing Huang, Northwestern University, 2014 AVS Prairie Chapter Early Career
Awardee: “Soft Carbon Sheets: Curiosities and Discoveries”
9:40 Allen Hall, University of Illinois at Urbana–Champaign, “Nanopillar Light-Absorbing
CuIn(1-x)GaxSe2 Thin Films Grown Through High Flux, Low Energy Ion Irradiation
Methods”
10:00 Xueqiang Zhang, Notre Dame, “Dynamic H2O/GaP (110) Interfacial Chemistry Tracked
by Near Ambient Pressure XPS in Real Time”
10:20 – 10:50 Coffee Break
Session 2: Moderator, Brittni Qualizza, Loyola
10:50 Michael Sailor, University of California – San Diego, “Surface Chemistry of
Luminescent Porous Silicon Nanoparticles”
11:30 Peng Wang, Argonne National Lab, “Photo-induced Electron Transfer Pathways in
Reduced Graphene Oxide-Hybrid Nano-Bio Catalyst”
11:50 Fanny Rodolakis Simones, Argonne National Lab, “Surface Attenuation of the
Quasiparticles at the Metal-Insulator Transition in Vanadium Oxides”
12:10 – 1:30 Lunch and Poster Session (MPR South); Chapter Business Meeting (MPR North)
Session 3: Moderator, Rachael Farber, Loyola
1:30 Bruce Koel, Princeton University, “Structure, Reactivity, and Nanotemplating at
Multimetallic Electrocatalyst Surfaces”
2:10 Adina Lucian-Mayer, Argonne National Lab, “Scanning Tunneling Microscopy and
Spectroscopy Studies of Graphene
2:30 S. Alex Kandel, Notre Dame, “Self-Assembly of Quasicrystalline Monolayers”
2:50 – 3:40
Coffee Break and Poster Session
Session 4: Moderator, Dan Killelea, Loyola
3:40 Keith Brown, Northwestern University, “Desktop Nanofabrication with Cantilever-Free
Scanning Probes”
4:00 Marvin Cummings, Argonne National Lab, “Synchrotron X-ray Scanning Tunneling
Microscopy (SXSTM) at the Advanced Photon Source”
4:20
Awards Ceremony
4:30 Joseph Lyding, University of Illinois at Urbana–Champaign, 2014 AVS Prairie Chapter
Outstanding Research Awardee: “Scanned Probe Based Nanofabrication and
Nanostructure Analysis”
5:10
Closing of Symposium
2014 AVS Prairie Chapter Symposium
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Notes
2014 AVS Prairie Chapter Symposium
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2014 AVS Prairie Chapter Symposium
Loyola University Chicago
Poster Presentations
#
1
2
Presenter
Jon Derouin
Rachael Farber
Affiliation
LUC
LUC
3
Zach Hund
UChicago
4
Andrew Koltonow
Northwestern
5
Deepti Krishnan
Northwestern
6
Joel Krooswyk
UIC
7
Wenxin Li
UChicago
8
Xiaohan Liu
UIC
9
Martin McBriarty
Northwestern
10
Lilly Mao
Northwestern
11
Antonio Mei
UIUC
12
Brittni Qualizza
LUC
13
Jonathan Raybin
UChicago
14
Yuan Ren
UIC
15
Rachel Seibert
IIT
16
Alexander Smith
Northwestern
17
Esin Soy
UIC
18
Mohit Tuteja
UIUC
19
Chris Williams
Indiana
20
Che-Ning Yeh
Northwestern
21
Jonathan Emery
ANL
22
Kalyan Raidongia
Northwestern
23
Nozomi Shirato
ANL
2014 AVS Prairie Chapter Symposium
Title
Investigation of the Interaction of Oxygen and Nickel
Water Adsorption on Pt(111) and Stepped Pt Surfaces
The Interaction of Organic Adsorbate Vibrations with
Substrate Lattice Waves in Methyl-Si(111)-(1x1)
Solution configurations of graphene oxide sheets
Graphene Oxide Assisted Hydrothermal Carbonization of
Carbon Hydrates
C2 Hydrogenation at Ambient Pressure on Pt(111)
Formation of Stabilized Ketene Intermediates in the
Reaction of O(3P) with Oligo(Phenylene Ethynylene)
Thiolate Self- Assembled Monolayers on Au(111)
Exactly-Doped Semiconductor Quantum Dots
Atomic Scale Structure-Chemistry Relationships at Model
Oxide Catalyst Surfaces: (V,W) / a-Al2O3 (0001)
Tuning the Water Contact Angle of Si Substrates to
Overcome the Rupture of Graphene Oxide Membranes
Suspended Over Micron-Sized Wells
Dynamic and structural stability of cubic Vanadium
Nitride
Reaction of Acene Surfaces Using the Diels-Alder
Reaction
Pattern Control in Diblock Copolymers and the Creation
of Functional Nanomaterials for Trace Gas Localization
and Detection
Thermal decomposition of ethylene on Ru(001)
Chemical Analysis of Pd and Ag Interaction with 3C-SiC
Thin Films
Repurposing Blu-ray Movie Discs as Low-cost, Quasirandom Nanoimprinting Templates for Photon
Management
Fabrication of Pt and Rh nanoclusters on a graphene
moiré pattern on Cu(111)
Low temperature photoluminescence studies on sputter
deposited CdS/CdTe junctions and solar cells
Assembly and Characterization of Supramolecular
Porphyrin Architectures at Metal Surfaces
Graphene Oxide Membrane in Water: To Disintegrate or
Not to Disintegrate
Atomic Layer Deposition of Metastable b-Fe2O3 via
Isomorphic Epitaxy for Photo-assisted Water Oxidation
Nanofluidic Ion Transport through Restacked 2D
Nanomaterials
Low Temperature Synchrotron X-ray Scanning Tunneling
Microscopy (LT-SXSTM)
9
Notes
2014 AVS Prairie Chapter Symposium
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Session 1; 9:00 am
AVS Prairie Chapter 2014 Early Career Research Awardee
Soft Carbon Sheets: Curiosities and Discoveries
Jiaxing Huang
Department of Materials Science and Engineering
Northwestern University, Evanston, IL 60208 USA
Graphite oxide sheets, now called graphene oxide (GO), are made by exfoliation of graphite
using century-old chemical reactions. Interest in this old material has resurged with the rapid
development of graphene since 2004, as GO is considered to be a promising precursor for bulk
production of graphene. Apart from making graphene, GO itself also has many intriguing
properties. For example, GO can be viewed as a two-dimensional (2D) soft material such as
polymer, highly anisotropic colloid that can form liquid crystals, membrane, or 2D surfactant. In
this talk, some curiosity driven discoveries will be shared such as the use of GO as surfactant to
process insoluble materials in water. GO sheets are also 2D building blocks to construct massive
arrays of 2D nanofluidic channels with high ionic conductivity. A few problems associated with the
manufacturing and processing of GO and its graphene product will be discussed, such as the
difficulties of imaging these single atomic layers and their ease of aggregation during processing.
Strategies and solutions to address these problems will be introduced.
2014 AVS Prairie Chapter Symposium
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Session 1; 9:40 am
Nanopillar Light-Absorbing CuIn(1-x)GaxSe2 Thin Films Grown
Through High Flux, Low Energy Ion Irradiation Methods
Allen J. Hall*1, Xiaoqing He1, Mohit Tuteja1, Angel Yanguas-Gil2 and Angus A. Rockett1
1
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign,
1304 W. Green St., Urbana, IL, 61801, USA, 2Argonne National Laboratory, 9700 S. Cass Avenue,
IL, 60438, USA
A hybrid effusion/sputtering vacuum system was modified with an inductively coupled
plasma (ICP) coil enabling ion assisted physical vapor deposition of CIGS thin films. To date two
methods utilizing low energy high flux ions have been found which produce deep black nanopillar
array thin films capable of absorbing more than 95% of incident light over a wide bandwidth and
wide range of angles of incidence similar to the moth’s eye structure. In a single-stage process, iPVD growth utilizing Cu, In, CuGa sputtering sources and effused Se gas produces CIGS nanopillar
arrays with very flat tops and facetted sides. In a two-stage process, a room temperature deposited
metal alloy film is selenized into nanopillar arrays of CIGS material. In both growths, etching and
redeposition was found to occur, while physical bombardment was determined to play little role.
Single stage growth is believed to be a modification of standard vapor-solid physical deposition;
while two-stage growth is surmised to be an ion-mediated vapor-liquid-solid growth. TEM, XRD
and EBSD shows both films are crystalline CIGS material, and that the nanopillars in both cases are
textured towards the {112}T plane normal, even when grown on (001) GaAs. Chemical bath
deposition of CdS heterojunction partner and subsequent finishing of the device by ALD-TCO
depositions keeps the deep black nature of the films intact. The hybrid iPVD effusion/sputtering
growth and bath deposition is scalable to industrial levels and may possibly afford methods to
produce highly absorbing nanostructured CIGS and related material thin films.
2014 AVS Prairie Chapter Symposium
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Session 1; 10:00 am
Dynamic H2O/GaP (110) Interfacial Chemistry Tracked by Near
Ambient Pressure XPS in Real Time
Xueqiang Zhang1,2 and Sylwia Ptasinska1,3*
1
Radiation Laboratory, 2Department of Chemistry and Biochemistry, and 3Department of Physics,
University of Notre Dame, Notre Dame, IN 46556, USA
A photoelectrochemical (PEC) solar cell for water splitting has the potential to convert solar
energy into chemical energy and store it in the form of hydrogen, and is a promising candidate for
sustainable and clean fuels.1 The PEC solar cell with hitherto highest efficiency was achieved by
phosphide-based III-V semiconductors, which are, however, usually limited by photocorrosion or
decreased electron extraction efficiency due to the formation of interfacial oxide species. This issue
is especially important when operating electrodes (semiconductor) are exposed to aqueous
electrolytes.2, 3 Due to the lack of information related to atomic and electronic structures of a
semiconductor surface under realistic operation conditions, a comprehensive picture of molecular
chemistry at the water/electrode interface is still unknown. It is therefore desirable to understand the
process of water interactions with semiconductors and the possible oxidation and reduction
mechanisms at the H2O/semiconductor interface.
In the present study, water dissociative adsorption on GaP (110) surface was investigated using
near ambient pressure X-ray photoelectron spectroscopy (NAP XPS) at various pressures and
temperatures. The dynamic interfacial chemistry was monitored by the photoemission spectra of Ga
2p3/2, O 1s and P 2p recorded in real time. In the pressure-dependent study performed at room
temperature (~300 K), the enhanced surface Ga hydroxylation and oxidation was observed with the
increase of water vapor pressure. In the temperature-dependent study, continuous enhancement of
surface Ga hydroxylation and oxidation was observed at temperatures below 673 K. While a largescale conversion of surface O-Ga-OH species, into non-stoichiometric Ga hydroxide, along with
surface P oxidation, was observed in the photoemission spectra at a temperature of 773 K. These
results can be compared with recent theoretical findings4, 5 and lead to a better understanding of
water splitting mechanisms and photo-corrosion on semiconductor surfaces.
References
1.
H.-J., L.; Peter, L., Photoelectrochemical Water Splitting: Materials, Processes and Architectures; Royal
Society of Chemistry: Cambridge, GBR, 2013.
2.
Khaselev, O.; Turner, J. A. A Monolithic Photovoltaic-Photoelectrochemical Device for Hydrogen Production
Via Water Splitting. Science 1998, 280, 425-427.
3.
Lewerenz, H. J.; Heine, C.; Skorupska, K.; Szabo, N.; Hannappel, T.; Vo-Dinh, T.; Campbell, S. A.; Klemm,
H. W.; Munoz, A. G. Photoelectrocatalysis: Principles, Nanoemitter Applications and Routes to Bio-Inspired Systems.
Energ. Environ. Sci. 2010, 3, 748-760.
4.
Wood, B. C.; Schwegler, E.; Choi, W. I.; Ogitsu, T. Hydrogen-Bond Dynamics of Water at the Interface with
InP/GaP(001) and the Implications for Photoelectrochemistry. J. Am. Chem. Soc. 2013, 135, 15774-15783.
5.
Munoz-Garcia, A. B.; Carter, E. A. Non-innocent Dissociation of H2O on GaP(110): Implications for
Electrochemical Reduction of CO2. J. Am. Chem. Soc. 2012, 134, 13600-13603.
2014 AVS Prairie Chapter Symposium
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Session 2; 10:50 am
Surface Chemistry of Luminescent Porous Silicon Nanoparticles
Michael J. Sailor
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
The electronic and optical properties that make the semiconductor silicon so useful for solidstate devices such as solar cells and microelectronics can also be harnessed for biological
applications. This presentation will discuss the chemistry and photochemistry of nanostructured
porous silicon. The intrinsic photoluminescence that derives from quantum confinement and
surface defect states provides a non-toxic and biodegradable luminescent probe for in vivo and in
vitro imaging. The luminescence properties are intimately tied to the surface chemistry of the
material, and the relatively long (microseconds) excited state lifetime of this material can be
harnessed for time-gated imaging or chemical sensing. Applications in sensing, drug delivery, and
targeted therapies will be discussed.
Porous Si nanoparticles generated by pulsed electrochemical etching of silicon wafers. (left)
The particles, on the order of 100-200 nm, possess intrinsic photoluminescence useful for in vitro or
in vivo sensing. (right) Confocal microscope image of dendritic cells (green) containing porous Si
nanoparticles (red). Intrinsic NIR fluorescence from the quantum-confined Si nanostructures shown
in red; green in image is cellular membrane stain. A targeting antibody induced internalization of
the nanoparticles in the cells. Scale bar in the right image is 40 µm.
2014 AVS Prairie Chapter Symposium
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Session 2; 11:30 am
Photo-induced Electron Transfer Pathways in Reduced Graphene
Oxide-Hybrid Nano-Bio Catalyst
Peng Wang*1
1
Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439,
Photocatalytic production of hydrogen from water under sunlight has attracted remarkable
attention due to the increasing global energy demand.1,2 In this presentation, reduced graphene
oxide (rGO) and a membrane protein bacteriorhodopsin (bR) were used to harness visible light by a
Pt/TiO2.3 The rGO enhances the nano-bio catalyst performance resulting in hydrogen production
rates of approximately 11.24 mmol of H2 (µmol protein)-1 h-1. A 9-fold increase in photocurrent
density has been confirmed when TiO2 electrodes were modified with rGO and bR. Electron
paramagnetic resonance and transient absorption spectroscopy show the electron transfer from rGO
to the semiconductor under visible light.
Figure 1. Schematic diagram of photocatalytic hydrogen evolution using Pt/TiO2-rGO-bR.
Acknowledgment: This work was performed at the Center for Nanoscale Materials, a U.S.
Department of Energy, Office of Science, Office of Basic Energy Sciences User Facility under
Contract No. DE-AC02-06CH11357.
References
1. Maeda, K.; Teramura, K.; Lu, D. L.; Takata, T.; Saito, N.; Inoue, Y.; Domen, K. Nature
2006, 440, 295.
2. Wang, P.; Balasubramanian, S.; Schaller, R. D.; Rajh, T.; Rozhkova, E. A. Nano Lett. 2013,
13, 3365.
3. Wang, P.; Dimitrijevic, N. M.; Chang, A. Y.; Schaller, R. D.; Liu, Y. Z.; Rajh, T.;
Rozhkova, E. A. ACS Nano 10.1021/nn502011p.
2014 AVS Prairie Chapter Symposium
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Session 2; 11:50 am
Surface Attenuation of the Quasiparticles at the Metal-Insulator
Transition in Vanadium Oxides
Fanny Rodolakis Simoes*N, B. Mansart M, E. Papalazarou P, S. Gorovikov Q, P. Vilmercati R,L.
Petaccia R, A. Goldoni R, J. P. Rueff S, S. Lupi T, P. Metcalf U, and M. MarsiP
N
Argonne National Laboratory (Argonne, IL), MESPCI ParisTech (Paris, France), PLPS (Orsay,
France), QCLS (Saskatoon, SK), RElettra (Trieste, Italy), SSOLEIL (Saclay, France),
T
Universita di Roma (Roma, Italy), U Purdue University (West Lafayette, IN)
Collective electronic excitations are at the heart of many open issues in condensed matter
physics, and present peculiar properties that are intrinsically different from those of the individual
electrons that originate them. To study electronic properties of such strongly correlated systems, a
bulk sensitive probe is known to be essential: for example, a surface layer can present an insulating
behavior while the bulk is metallic, which is normally attributed to the fact that at the surface
electron correlation effects are more relevant. Understand what is specific to collective electronic
excitations that makes the effect of the surface more pronounced requires further attention. To
address that issue, we have performed angle resolved photoemission at very low photons energy
(i.e. increased bulk sensitivity) in two vanadium oxides displaying correlation induced metalinsulator transition as a function of temperature, doping and pressure: (V1−xCrx)2O3 and VO2
vanadium oxides. A clear quasiparticle peak (QP) is observed at low energy in the metallic phase of
both compounds: this QP is the spectral signature of the coherent excitations in the vicinity of the
Fermi energy. By measuring the variation of its intensity for different probing depths, we have
investigated the behavior of the QP at the surface and demonstrated the existence of a surface dead
layer below the surface where correlated electronic states behave differently. This length scale,
which is larger than the thickness of the surface region as normally defined for non-correlated
electronic states, seems to be an intrinsic, bulk property of the system and is found to increase when
approaching the Mott transition.
2014 AVS Prairie Chapter Symposium
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Session 3; 1:30 pm
Structure, Reactivity, and Nanotemplating at Multimetallic
Electrocatalyst Surfaces
Bruce E. Koel
The Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ
08544
Pt and Pt-based materials are widely used as electrocatalysts in energy-related applications
such as fuels cells and hydrogen production, but suffer from drawbacks related to cost, inefficiency,
and low durability. We report on investigations of Pt-monolayer based and non-Pt electrocatalysts
to reduce Pt loadings or replace Pt electrocatalysts while maintaining or even enhancing activity
with improved stability. Fundamental studies of surface-science based, model alloy and metalmonolayer electrocatalysts with well-controlled surface composition and surface structure provide
insight into key factors that control electrocatalytic reactions on multimetallic systems. Three
electrocatalysts were prepared in vacuum, characterized using surface science techniques, and
evaluated for their electrocatalytic activity for the oxygen reduction reaction (ORR), hydrogen
evolution reaction (HER), and ethanol oxidation (EO): (i) Au sub-monolayer on Pd3Fe(111); (ii) Pt
monolayer on nanofaceted surfaces of C/Re(11-21) and O/W(111); and (iii) Pt monolayer on
polycrystalline Hf-Ir.
2014 AVS Prairie Chapter Symposium
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Session 3; 2:10 pm
Scanning Tunneling Microscopy and Spectroscopy Studies of
Graphene
Adina Luican-Mayer*1, Eva Y. Andrei2, Saw Wai-Hla 1
1
Center for Nanoscale Materials, Argonne National Lab, 2Department of Physics, Rutgers
University
Seeking to understand the unique nature of the charge carriers in graphene, we performed
scanning tunneling microscopy (STM) and spectroscopy (STS) experiments at low temperatures
and in magnetic field. These techniques give access, down to atomic scales, to structural
information as well as to the density of states. In the first part of the talk, I will discuss experimental
results studying twisted graphene layers away from the equilibrium Bernal stacking which leads to
the formation of Moiré patterns. Our experiments demonstrate the effect of such rotations on the
electronic properties as a function of twist angle1. In the second part, I will present studies of
Landau quantization and its dependence on charge carrier density. Measurements were carried out
on exfoliated graphene samples deposited on SiO2, which allowed tuning the carrier density through
the Si back-gate. Furthermore, by performing spatially resolved STS, we demonstrate the true
discrete quantum mechanical electronic spectrum within the Landau level band near an impurity in
graphene in the quantum Hall regime2. Lastly, I will discuss our recent progress in fabricating and
characterizing stacks of atomically thin Van der Waals materials, in particular the charge density
wave system, 1T-TaS2.
References
1. Adina Luican-Mayer and Eva Y. Andrei, Scanning Tunneling Microscopy and Spectroscopy
studies of graphene, book chapter in “Physics of Graphene”, editors H. Aoki and M. S.
Dresselhaus , Nanoscience and Technology series Springer p28 (2014)
2. Adina Luican-Mayer, Maxim Kharitonov, Guohong Li, Chih-Pin Lu, Ivan Skachko, Alem-Mar
B. Goncalves, K. Watanabe, T. Taniguchi, and Eva Y. Andrei, Screening Charged Impurities and
Lifting the Orbital Degeneracy in Graphene by Populating Landau Levels. Phys. Rev. Lett.
(2014)
2014 AVS Prairie Chapter Symposium
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Session 3; 2:30 pm
Self-Assembly of Quasicrystalline Monolayers
S. Alex Kandel
Department of Chemistry and Biochemistry, University of Notre Dame; Notre Dame, IN 46556
Self-assembled monolayers on surfaces
typically have long-range order as the result of noncovalent intermolecular interactions. Carboxylic acids
can be particularly good structural elements for selfassembly, as the COOH group acts as both a donor and
acceptor for the formation of hydrogen bonds. In most
cases of self-assembly, carboxylic acids will dimerize
to maximize hydrogen-bonding interactions.
For
ferrocene carboxylic acid (FcCOOH), however, the
ability of the aromatic C-H bond to act as a weak Hdonor stabilizes larger O-H-O angles, resulting in the
formation of cyclic polymers and, in particular,
symmetric cyclic pentamers. These pentamers cocrystallize with FcCOOH dimers to give long-range
orientational order as well as translational order
without periodicity; that is, a monolayer can be created
that is quasicrystalline.
Scanning tunneling
microscopy and density functional theory are used to
determine what structures can be formed as well as to elucidate the mechanisms responsible for
their formation. The possibilities for extending these bonding motifs to other supramolecular
systems will be discussed.
2014 AVS Prairie Chapter Symposium
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Session 4; 3:40 pm
Desktop Nanofabrication with Cantilever-Free Scanning Probes
Keith A. Brown*N, Daniel J. EichelsdoerferN, Xing LiaoM, and Chad A. MirkinN,M
N
Department of Chemistry and International Institute for Nanotechnology, Northwestern
University, M Department of Materials Science and Engineering, Northwestern University
The availability of reliable nanofabrication methods has dictated the pace of progress in
many areas of physics, materials science, electronics, and biotechnology. A major deficiency in
these fields is our inability to simultaneously control the architecture of soft materials from
macroscopic to nanoscopic length scales. Scanning probe instruments, such as the atomic force
microscope, are promising platforms for nanofabrication because they provide direct access to the
nanoscale. However, the central barrier to their widespread use as lithographic instruments is
throughput, as it is prohibitively slow to pattern large areas with a single nanoscale probe. To
address this challenge, we explored a new architecture that utilizes a thin elastomeric film on a glass
slide in lieu of cantilevers to enable the use of a massive array of probes in a simple format.
Unfortunately, these cantilever-free probe arrays are passive duplication tools where each probe
writes a copy of the same pattern. Here, we report on our recent advances in developing techniques
for actuating individual probes in cantilever-free arrays and discuss the new scientific directions that
these advances enable. Specifically, we present methods for both physically actuating cantileverfree probes using local heating1,2 and optically addressing probes that function as light valves for
near-field photolithography,3 and find both to be capable of stitching together high resolution
patterns that span multiple probes. These advances in nanofabrication have enabled new types of
experiments, and in particular, we present recent progress exploring the combinatorial study of
biochemical interactions and the high throughput fabrication of functional metamaterials using
cantilever-free techniques. Taken together, these observations indicate that versatile desktop
nanofabrication is possible using scanning probes and that these techniques can address the
emerging challenges related to patterning soft materials.
(1)
(2)
(3)
Brown, K. A., et al. Proc. Natl. Acad. Sci. USA 2013, 110, 12921.
Brown, K. A., et al. J. Vac. Sci. Technol., B 2013, 31, 06F201.
Liao, X., et al. Nat. Commun. 2013, 4, 2103
2014 AVS Prairie Chapter Symposium
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Session 4; 4:00 pm
Synchrotron X-ray Scanning Tunneling Microscopy (SXSTM) at the
Advanced Photon Source
M. Cummings*1, N. Shirato1, B. Stripe1, C. Preissner1, D. Rosenmann2, S.-W. Hla2, V. Rose1,2
1
Advanced Photon Source, 2 Center for Nanoscale Materials
One fundamental challenge in surface science that inhibits our understanding of nano-scale
surface phenomena is our inability to collect pertinent, localized information about the chemical
electronic and magnetic nature of a sample surface with sub-nanometer to molecular-scale
resolution. Variants of the scanning probe microscope can provide detailed information about the
atomic and electronic surface structure, but do not easily yield direct chemical information.
Advanced x-ray microscopy techniques (photoemission electron microscopy) yield chemical
information, but typically, do not provide spatial resolutions beyond a few tens of nanometers.
Currently, we are developing a new in-situ synchrotron x-ray scanning tunneling microscope
(SXSTM) at Argonne National Laboratory’s Advanced Photon Source. The new high-resolution
microscopy technique takes full advantage of the chemical, electronic and magnetic sensitivities
that synchrotron x-ray radiation offers and combines this with the sub-nanometer spatial resolution
of the scanning tunneling microscope. Utilizing this technique, we have demonstrated the
capability to image nano-scale materials with chemical contrast. [1,2]
Recent studies also indicate the plausibility of localized sub-nanometer scale x-ray magnetic
circular dichroism (XMCD) measurement utilizing SXSTM instrumentation. The potential to
perform sub-nanometer scale XMCD measurements at the surface would allow one to study the
impact of local magnetic structure (atomic-scale defects, domain walls propagation) on real-world,
nanotechnology-based material systems. SXSTM could prove a powerful surface characterization
technique and potentially enhance our understanding of nano-scale physical phenomena at the
surface.
This work was funded by the Office of Science Early Career Research Program through the
Division of Scientific User Facilities, Office of Basic Energy Sciences of the U.S. Department of
Energy through Grant SC70705. Work at the Advanced Photon Source, the Center for Nanoscale
Materials, and the Electron Microscopy Center was supported by the U. S. Department of Energy,
Office of Science, Office of Basic Energy Sciences, under contract DE-AC02-06CH11357.
[1] http://www.aps.anl.gov/Xray_Science_Division/Sxspm/
[2] U.S. Patent Application 13/791,157
2014 AVS Prairie Chapter Symposium
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Session 4; 4:30 pm
AVS Prairie Chapter 2014 Outstanding Research Awardee
Scanned Probe Based Nanofabrication and Nanostructure Analysis
Joseph W. Lyding
Department of Electrical and Computer Engineering and Beckman Institute, University of Illinois,
Urbana, IL 61801, USA
One nanotechnology scenario is the development of hybrid schemes that involve integration
with standard platforms such as silicon. As a step in this direction, we have developed the STMbased hydrogen resist process in which hydrogen serves as an atomic layer electron resist. STM
electrons can desorb this hydrogen with atomic precision to create templates for selective chemistry.
Aside from exploring nanofabrication possibilities, we have looked in detail at this electron-induced
desorption process. Two desorption regimes are observed. At higher electron energies, Si-H bonds
are broken by direct excitation from the bonding-to-antibonding state, whereas at lower voltages
vibrational heating leads to desorption from “hot” ground state. A technology spin-off of these
experiments is the use of deuterium to enhance the lifetime of the CMOS processors in the cell
phones vibrating in your pockets. We have also used silicon and the III-V semiconductors GaAs
and InAs as supports for carbon nanotubes and graphene. Using a simple process that we call dry
contact transfer (DCT), we can deposit nanostructures onto atomically clean surfaces in ultrahigh
vacuum. Examples will be presented including the subtle dependence of carbon nanotube electronic
structure on the underlying lattice orientation, and the first observation of the metallic zigzag edge
state in graphene. This talk will also show results for the use of electron-beam induced deposition to
create sub-5nm metal wires for contacting nanostructures, the used of a graphene shrink wrap to
study aqueous systems in UHV, a SPM probe sharpening technique for producing 1 nm radii
probes, and a new technique for increasing the performance of carbon nanotube array transistors by
an order of magnitude.
2014 AVS Prairie Chapter Symposium
22
Poster Abstracts
2014 AVS Prairie Chapter Symposium
23
P1
Investigation of the Interaction of Oxygen and Nickel
Jonathan Derouin and Dan Killelea
Student Poster Award Contestant
Department of Chemistry & Biochemistry, Loyola University Chicago, Chicago, IL 60660
Understanding the interaction of oxygen with metal surfaces is important in the study of corrosion
and catalysis. The nickel/oxygen system has been studied extensively due to its importance in
heterogeneous catalysis and use in hydrogen production and fuel cells. Oxygen adsorption on
nickel also serves as a model system for dissociative chemisorption. Our research uses UHV-STM,
Auger electron spectroscopy and temperature programmed desorption to study the interaction of
oxygen with Ni(111) and Ni(110) single crystals. With these techniques, we are studying how
defects such as step edges on the different crystal faces affect oxygen adsorption and incorporation
into the subsurface. The goal of the study is to elucidate the fundamental dynamics of the
interaction between oxygen and nickel from sub-monolayer coverage through the formation of NiO
films.
2014 AVS Prairie Chapter Symposium
24
P2
Water Adsorption on Pt(111) and Stepped Pt Surfaces
R.G. Farber1, L.B.F. Juurlink2, and D.R. Killelea1
Student Poster Award Contestant
1
Department of Chemistry & Biochemistry, Loyola University Chicago, Chicago, IL, USA,
Catalysis and Surface Chemistry, Leiden Institute of Chemistry, Leiden, The Netherlands
2
The interaction of water with metal surfaces has attracted much attention in the field of surface
science. Water is ubiquitous on earth and is therefore of high significance to a wide range of fields,
from studies of material aging and corrosion to atmospheric science. Studies of the adsorption,
wetting, and desorption of water on metal surfaces continues to reveal new, and sometimes
surprising, information about this deceptively simple system. Most relevant to this work are more
recent advances in understanding the structures formed by submonolayer coverages of water on
metal surfaces. Progress in this avenue has been facilitated by a combination of atomically resolved
imaging experiments with density functional theory (DFT) calculations to elucidate how the balance
of the water-water and water-surface interactions yield the bonding patterns and behavior of water
on regular metal surfaces [1]. As the application of these methods continues to develop, the
understanding of 2-D water cluster formation and bonding behavior has given greater insight into
the unique chemistry displayed by water on metal surfaces
Thus far, most studies have focused on the interaction of water with flat, regular metal surfaces;
the still emerging studies of water on terrace step edges has further added to this already rich field
[2]. In this project, we will study the arrangements of small clusters of water molecules on highly
stepped, or curved, Pt surfaces and compare the submonolayer coverage clusters on the stepped
surfaces to those found on planar surfaces. We begin our study by first imaging water clusters on a
Pt(111) crystal surface using an ultra-high vacuum scanning tunneling microscope (UHV-STM).
We will then move on to studying the stepped surfaces. We will compare our observations to the
predictions from DFT calculations of the same system [3]. The information gathered in this project
will not only give further insight into water’s unique behavior on metal surfaces, but also provide
information on water’s behavior on more reactive surface sites. It is known that in nanoscale
experiments, areas with defects are more reactive than flat and regular areas. An understanding of
how steps and defects perturb the delicate balance of water-water and water-substrate interactions
will result from this study.
References:
[1] A. Hodgson; S. Haq; Surf. Sci. Rep. 64 381 (2009).
[2] M. van der Niet; A. den Dunnen; L.B.F. Juurlink; M.T.M. Koper; PCCP 13 1629 (2011)
[3] M.J. Kolb; F. Calle-Vallejo; L.B.F. Juurlink, M.T.M. Koper; JCP 140 134708 (2014)
2014 AVS Prairie Chapter Symposium
25
P3
The Interaction of Organic Adsorbate Vibrations with Substrate
Lattice Waves in Methyl-Si(111)-(1x1)
Zachary M Hund1 , Ryan D. Brown1, Davide Campi2, Leslie E. O'Leary3, Nathan S. Lewis3, Marco
Bernasconi2, Giorgio Benedek2, Steven J. Sibener1
Student Poster Award Contestant
1
University of Chicago, 2Universita di Milano-Bicocca, 3California Institute of Technology,
4
Univerisdad del Pais Vasco
A combined helium atom scattering and density functional perturbation theory study has
been performed to elucidate the surface phonon dispersion relations for both the CH3-Si(111)-(1x1)
and CD3-Si(111)-(1x1) surfaces. The combination of experimental and theoretical methods has
allowed characterization of the interactions between the low energy vibrations of the adsorbate and
the lattice waves of the underlying substrate, as well as characterization of the interactions between
neighboring methyl groups, across the entire wavevector resolved vibrational energy spectrum of
each system. The Rayleigh wave was found to hybridize with the surface rocking libration near the
surface Brillouin zone edge at both the M-point and K-point. The calculations indicated that the
upper and lower bounds of the energy barrier for the methyl rotation about the Si-C axis were
sufficient to prevent the free rotation of the methyl groups at a room temperature interface. The
density functional perturbation theory calculations revealed several other surface phonons that
experienced mode-splitting arising from the mutual interaction of adjacent methyl groups. The
theory identified a Lucas pair that exists just below the silicon optical bands. For both the CH3- and
CD3-terminated Si(111) surfaces, the deformations of the methyl groups were examined and
compared to previous experimental and theoretical work on the nature of the surface vibrations.
The calculations indicated a splitting of the asymmetric deformation of the methyl group near the
zone edges due to steric interactions of adjacent methyl groups. The observed shifts in vibrational
energies of the -CD3 groups were consistent with the expected effect of isotopic substitution in this
system.
2014 AVS Prairie Chapter Symposium
26
P4
Solution Configurations of Graphene Oxide Sheets
Andrew Koltonow1, Bernard Beckerman1, Jiayan Luo2, Erik Luijten1, Jiaxing Huang1
Student Poster Award Contestant
1
Northwestern University, 2Tianjin University
Despite the intense research interest garnered by graphene oxide, the solution configuration
of graphene oxide sheets is still a matter of dispute. Simulation seems to suggest that sheets can
exist as crumpled balls, but there is no compelling direct observation of this. We use collective
assembly behaviors as a marker to probe the conformation of 2D membranes in solution. We have
used this approach to carry out the first direct in-situ study of the conformation of graphene oxide in
mixed solvents. Combining our observations with molecular dynamics simulations and radiation
scattering experiments, we find that GO does not spontaneously form crumpled and collapsed balls
in solution, but that such conformations can be formed by applying a confining force.
2014 AVS Prairie Chapter Symposium
27
P5
Graphene Oxide Assisted Hydrothermal Carbonization of Carbon
Hydrates
Deepti Krishnan1, Kalyan Raidongia1, Jiaojing Shao2, Jiaxing Huang1
Student Poster Award Contestant
1
Northwestern University, 2Tianjin University
Biomass is a cheap, ecofriendly and renewable raw material for the production of functional
carbonaceous materials. Hydrothermal carbonization (HTC) of biomass typically produces carbon
materials that are insulating. Using simple carbon hydrates such as glucose and cellulose as a model
system for biomass, here we demonstrate that graphene oxide (GO) sheets can promote HTC
conversion. Adding a very small amount of GO to glucose (e.g., 1:800 weight ratio) can
significantly alter the morphology of its HTC product, resulting in more conductive carbon
materials with higher degree of carbonization. HTC treatment of glucose is known to produce a
dispersion of micron sized carbon spheres. In the presence of GO, HTC treatment results in
dispersed carbon platelets of tens of nanometers in thickness at low mass loading level, and freestanding carbon monoliths at high mass loading levels. Control experiments with other carbon
materials such as graphite, carbon nanotubes and carbon black show that only GO has significant
effect in promoting HTC conversion, likely due to its good water processability, amphiphilicity and
two-dimensional structure that may help to template the initially carbonized materials. GO offers an
additional advantage in that its graphene product can act as an in-situ heating element to enable
further carbonization of the HTC carbon monoliths upon microwave irradiation. Similar effect of
GO is also observed for the HTC treatment of cellulose.
2014 AVS Prairie Chapter Symposium
28
P6
C2 Hydrogenation at Ambient Pressure on Pt(111)
Joel Krooswyk, Michael Trenary
Student Poster Award Contestant
Department of Chemistry, University of Illinois at Chicago, 845 W Taylor Street, Chicago, IL
60607
Carbon has been shown to be the decomposition product from catalytic reactions involving
hydrocarbons adsorbed on metal catalysts. Its presence reduces the amount of active surface sites
available during a reaction. The decomposition products from adsorbed acetylene and ethylene on
Pt(111) are C2 and C1 species, respectively. A previous UHV study showed that C2H2 adsorbed on
Pt(111) at 750 K immediately decomposes to mostly C2 species. H2 was then coadsorbed with C2 at
85 K and annealed to 400 K, which produced ethylidyne (CCH3), ethynyl (CCH), and methylidyne
(CH) species. None of the species were hydrogenated to ethylene or ethane, and after annealing to
750 K, a percentage of the carbon on the surface could be rehydrogenated after cooling the crystal
to 300 K and coadsorbing H2.
In this study, the hydrogenation of C2 species in 1×10-2 to 1 Torr of H2 was monitored with
RAIRS. The species was created on Pt(111) with C2H2 adsorption at 750 K as done previously and
the crystal was cooled to 300 K. The crystal was then annealed in an ambient pressure of H2. The C2
species are hydrogenated to ethylidyne at 400 K and then to ethane at approximately 450-500 K.
This reaction is shown to be dependent on the pressure of H2. The results show that ethylidyne will
be hydrogenated at 450 and 500 K at 1.0 and 1×10-2 Torr H2, respectively. To show that the C2
species are fully hydrogenated and desorbed as ethane, which indicates that the surface is clean, CO
was leaked into the cell with H2. We observe after the 500 K anneal that the peak assigned to the
CO species is similar in intensity to one from CO adsorbed on a clean surface. This indicates that
there are no C2 species remaining on the surface. Also, the peak positions of the terminal and bridge
sites are shifted, which indicates that there is a high coverage of H atoms adsorbed on the surface.
2014 AVS Prairie Chapter Symposium
29
P7
Formation of Stabilized Ketene Intermediates in the Reaction of O(3P)
with Oligo(Phenylene Ethynylene) Thiolate Self- Assembled
Monolayers on Au(111)
Wenxin Li, Grant G. Langlois, Natalie A. Kautz, and S. J. Sibener
Student Poster Award Contestant
The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E 57th
Street, Chicago, Illinois 60637
We have taken steps to develop a methodology for observing and trapping organic reaction
intermediates by exposing well-ordered self assembled monolayers (SAM) to supersonic beams of
atomic oxygen. The use of a SAM stabilizes highly energetic intermediates formed from
bimolecular reactions at the interface due to rapid thermal equilibration with the SAM matrix. In
this poster we will discuss the elucidation of the mechanistic details for the fundamental reaction
between O(3P) and alkyne bonds by monitoring chemical and structural changes in an
oligo(phenylene ethynylene) SAM reacting with O(3P) under collision conditions having specified
initial reaction orientation. Utilizing time-resolved reflection-absorption infrared spectroscopy
(RAIRS) and scanning tunneling microscopy (STM) under ultrahigh vacuum conditions, we have
directly observed electrophilic addition of O(3P) onto the alkyne moieties, resulting in formation of
a ketene intermediate via phenyl migration. Under single-collision conditions in the gas phase the
vibrationally-excited ketene intermediate cleaves to release CO. In contrast to this, herein we have
directly observed the formation of the condensed-phase stabilized singlet ketene by RAIRS.
Moreover, we have also observed that the phenyl ring at the vacuum/film interface significantly
cants towards the substrate plane as a result of this reaction. STM images of the SAM taken before
and after O(3P) exposure show an expansion of the ordered lattice resulting from formation of the
new nonlinear molecular structures within the adsorbed film. This approach of using pre-oriented
reactive molecules in ordered SAMs in combination with angle and velocity selected energetic
reagents provides a general approach for probing the geometric constraints associated with the
reaction dynamics for a wide range of chemical reactions.
2014 AVS Prairie Chapter Symposium
30
P8
Exactly-Doped Semiconductor Quantum Dots
Xiaohan Liu,† Ali M. Jawaid,† Soma Chattopadhyay,‡ Tomohiro Shibata,‡ and Preston T. Snee†
Student Poster Award Contestant
† Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street, Chicago,
Illinois 60607-7061, United States, ‡ CSRRI-IIT, MRCAT, Argonne, National Laboratory, Sector
10, Building 433B, Argonne, Illinois 60439
Progress on the synthesis of colloidal semiconductor quantum dots (QDs) has largely
focused on simple binary systems such as ubiquitous CdSe QDs. Recently, the introduction of guest
impurities into such binary quantum confined systems has become topical. This is due to the fact
that the introduction of such impurities imparts a novel method for bandgap engineering beyond
that achievable with size control. Unfortunately, methods to synthesize doped QDs create samples
with a dispersion of properties as the number of dopants per dot is dictated by Poissonian statistics.
Lately, our group developed a strategy to synthesize QDs that contain an exact number of copper
impurities into CdSe, CdS, and InP QDs controllably.1 The results have enabled us to fully
characterize the photophysical properties of doped QDs. Specifically, we have recently
demonstrated that the photophysics of copper dopants is strongly host material-dependent in the
case of Cu-doped CdSe vs. CdS QDs.
Cluster-seed method for synthesizing quantum dots. The organometallic clusters
[Na(H2O)3]2[Cu4(SPh)6] act as nucleation points for the synthesis of the same number of QDs with four
copper (I) dopants.
Reference: 1. A. Jawaid et al., ACS Nano, 2013, 7, 3190–3197.
2014 AVS Prairie Chapter Symposium
31
P9
Tuning the Water Contact Angle of Si Substrates to Overcome the
Rupture of Graphene Oxide Membranes Suspended Over MicronSized Wells
Lily Mao*1, Jiaxing Huang1, SonBinh Nguyen1
Student Poster Award Contestant
1
Northwestern University
The deposition of Langmuir-Blodgett films of graphene oxide onto a solid Si substrate is
typically performed as a wet transfer process. However, when this substrate is patterned with an
array of micron-sized wells, the deposited membranes of graphene oxide monolayers often rupture
over the wells due to capillary forces. We hypothesize that by tuning the water contact angle of the
substrates, this rupture can be minimized. Indeed, when the deposition is carried out over substrates
that have water contact angles ≥ 60°, intact suspended membranes can be obtained. In contrast,
deposition over substrates possessing lower contact angles resulted in rupture of the suspended
membranes. This strategy could be extended to the fabrication of suspended membranes of
graphene oxide-containing nanocomposites as platforms for studying nanoscale properties.
2014 AVS Prairie Chapter Symposium
32
P10
Atomic Scale Structure-Chemistry Relationships at Model Oxide
Catalyst Surfaces: (V,W) / α -Al2O3 (0001)
Martin E. McBriarty1, Gavin P. Campbell1, Tasha L. Drake2, Jeffrey W. Elam3, Peter C. Stair2,
Donald E. Ellis2,4, and Michael J. Bedzyk1,4
Student Poster Award Contestant
1
Dept. of Materials Science and Engineering, Northwestern University, 2Dept. of Chemistry,
Northwestern University, 3Energy Systems Division, Argonne National Laboratory, 4Dept. of
Physics and Astronomy, Northwestern University
Tungsten oxide (WOX) promotes the selective catalytic reduction of nitric oxide (NO-SCR)
with ammonia over supported vanadium oxide (VOX) catalysts, but the atomic scale mechanism of
this V-W synergy is debated. We therefore investigate the structure and chemical properties of VOX
and WOX species prepared by atomic layer deposition (ALD) on the α-Al2O3 (0001) single crystal
surface under oxidizing and reducing conditions (350 °C in O2 and 400 °C in dilute H2,
respectively). X-ray photoelectron spectroscopy (XPS) and in situ synchrotron X-ray standing wave
(XSW) measurements show that the structure and chemical state of 0.9 ML WOX / α-Al2O3 (0001)
does not change significantly through oxidation-reduction cycling. However, 0.9 ML VOX
reversibly reduces from V5+ to mixed V5+/V4+ with a corresponding reversible increase in coherence
with the substrate lattice. The addition of VOX atop WOX yields similar results for each species,
although a slight reduction of WOX is observed in XPS. Density functional theory (DFT)
calculations of these surface compositions yield models that agree with experimental data. Analysis
of the DFT-calculated electronic structure reveals that upon addition of VOX to WOX / α-Al2O3
(0001), partially occupied W d-states near the Fermi energy appear which may contribute to the
Brønsted acidity of WOX and therefore improve the adsorption of NH3, the first step in the NO-SCR
reaction. Further calculations show that surface V-W interactions significantly enhance the
adsorption of NH3 relative to isolated V or W sites on α-Al2O3 (0001).
2014 AVS Prairie Chapter Symposium
33
P11
Dynamic and Structural Stability of Cubic Vanadium Nitride
A. B. Mei,1 O. Hellman,2 N. Wireklint,3 C. M. Schlepütz,4 D.G. Sangiovanni,2 B. Alling,2 I. A.
Abrikosov,2 A. Rockett,1 L. Hultman,2 J. E. Greene,1,2 and I. Petrov1,2
Student Poster Award Contestant
1
Department of Materials Science and the Materials Research Laboratory, University of Illinois,
104 South Goodwin, Urbana, IL 61801, 2 Thin Film Physics Division, Department of Physics
(IFM), Linköping University, SE-58183 Linköping, Sweden, 3 Department of Applied Physics,
Chalmers University of Technology, SE-41294 Götenburg, Sweden, 4 X-ray Science Division,
Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois
60439, USA
Structural phase transitions in epitaxial VN/MgO(011) thin films are investigated using
synchrotron x-ray diffraction (XRD), selected area electron diffraction (SAED), and ab-initio
molecular dynamics (AIMD). VN has the B1 NaCl structure at 300 K. However, low-temperature
XRD and SAED results reveal forbidden (00l) reflections of mixed parity, associated with a
tetragonal structure. The reflections appear at a critical transition temperature Tc = 250 K. Upon
cooling below Tc, the reflection intensities following the behavior, I α (Τc-T)1/2. Temperaturedependent VN resistivity ρ measurements between 4 and 300 K show that ρ(T) contains two linear
regions with distinct temperature coefficient of resistivities resulting from stronger electron-phonon
interactions in the tetragonal P42m structure than in the cubic Fm3m phase. VN conduction
electron mean free paths are determined as a function of temperature. These findings refute a longheld hypothesis that the VN resistivity exhibits sub-linear temperature dependence as electronphonon scattering reduce electron mean free paths to distances shorter than interatomic spacings.
The transport Eliashberg spectral function α2trF(ℏω), an energy-resolved measure of the
phonon density of states F(ℏω) and of the transport electron-phonon coupling strength α2tr(ℏω), is
determined and used in combination with AIMD-renormalized phonon dispersion relations to show
that anharmonic vibrations stabilize the NaCl phase dynamically and that the inclusion of
vibrational entropy, often-neglected in theoretical modeling, is essential for understanding the
room-temperature stability of NaCl-structure VN, and, in general, of material systems characterized
by large vibrational anharmonicities.
2014 AVS Prairie Chapter Symposium
34
P12
Reaction of Acene Surfaces Using the Diels-Alder Reaction
Brittni A. Qualizza1, Srividya Prasad1, M. Paul Chiarelli1, and Jacob. W. Ciszek1
Student Poster Award Contestant
1
Department of Chemistry and Biochemistry, Loyola University Chicago
Traditional surface reactions with inorganic substrates (like gold, silver, silicon and copper)
can have an influence on the properties of the bulk material, allowing for functionalization to
improve features like deterrence to oxidation, allowance for compatibility with biomolecules and
even the material’s electronic properties. These are properties which surface scientists seek to
investigate on organic materials as well. Using X-ray photoelectron spectroscopy (XPS) and
temperature programmed desorption (TPD) spectroscopy, tetracene single crystals were probed for
evidence of reaction with a series of molecules designed to form a monolayer of Diels-Alder
adducts on acene surfaces. The chemical identity of all the Diels-Alder adduct species formed on
our surfaces were confirmed by mass spectrometry, providing a facile method with which to append
molecules to these organic acene materials.
Above is a representation of a tetracene single crystal surface undergoing the Diels-Alder reaction with N-propylmaleimide.
2014 AVS Prairie Chapter Symposium
35
P13
Pattern Control in Diblock Copolymers and the Creation of
Functional Nanomaterials for Trace Gas Localization and Detection
Jonathan Raybin, Qianquan Tong, Hyung Ju Ryu, and Steven J. Sibener
Student Poster Award Contestant
The James Franck Institute and the Department of Chemistry, The University of Chicago
This poster presents our accomplishments in creating highly perfected diblock copolymer
substrates with potential applications as substrates for trace gas concentration and detection. These
experiments are detailed in a series of recent publications [1-5]. In brief, we have used
graphoepitaxy to guide the orientations of PS-b-PMMA in nanoconfining channels, leading to
alignment of the polymer domains along the channel direction. Using time-resolved AFM, this
platform was then used to examine how pairs of single defects interact and annihilate, yielding
information on single defect mobility kinetics. We have also examined defect mobility in tapered
channels, learning to control their directed mobility and ultimate placement. This is significant as
the resulting regularly-space defect arrays can be used to collect and localize trace contaminants or
functional nanomaterials. Next, using a crossed-channel architecture, we have engineered large
arrays of intersecting nanochannels with electric-field switchable connectivity maps, offering
applications for controllable circuits and nanofluidic devices. Finally, we have most recently used
these perfected polymer templates to guide the formation of highly-aligned arrays of gold nanorods,
which have demonstrated efficacy as a new class of Surface Enhanced Raman sensors.
1. Visualization of Individual Defect Mobility and Annihilation within Cylinder-Forming Diblock Copolymer in
Films on Nanopatterned Substrates, Qianqian Tong and S. J. Sibener, Macromolecules 46, 8528-8544 (2013).
2. Time-Resolved Analysis of Domain Growth and Alignment of Cylinder-Forming Block Copolymers Confined within
Nanopatterned Substrates, Hyung Ju Ryu, Qianqian Tong and S. J. Sibener, J. of Phys. Chem. Letters 4, 2890-2895
(2013).
3. Alignment and Structural Evolution of Cylinder-Forming Diblock Copolymer in Films in Patterned Width
Nanochannels, Qianqian Tong, Qin Zheng and S. J. Sibener, Macromolecules, Web Published June 16, 2014. DOI:
10.1021/ma500911y
4. Electric Field Induced Control and Switching of Block Copolymer Domain Orientations in Nanoconfined Channel
Architectures, Qianqian Tong and S. J. Sibener, J. Phys. Chem. C, Web Published, June 18, 2014. DOI:
10.1021/jp505677f
5. End-to-End Alignment of Gold Nanorods on Topographically Enhanced Cylinder-Forming Diblock Copolymer
Templates and their Surface Enhanced Raman Properties, Qianqian Tong, Edward W. Malachosky, Jonathan Raybin,
Philippe Guyot-Sionnest and S. J. Sibener, J. Phys. Chem. C, Accepted (2014)
2014 AVS Prairie Chapter Symposium
36
P14
Thermal Decomposition of Ethylene on Ru(001)
Yuan Ren, Iradwikanari Waluyo, and Michael Trenary
Student Poster Award Contestant
Department of Chemistry, University of Illinois at Chicago, 845 W Taylor Street, Chicago, IL
60607
Ruthenium is an important catalyst in the Fischer-Tropsch process which deals with the
conversion of syngas (CO and H2) into hydrocarbons. One of the most important aspects in the
Fischer-Tropsch reaction is the chain growth from a C1 species to longer chain hydrocarbons. It is,
therefore, important interesting to study the chemistry of various CxHy hydrocarbon fragments on
transition metal surfaces as building blocks in the chain growth mechanism. Ethylidyne (CCH3) is
an interesting hydrocarbon fragment that has been studied on many surfaces as the decomposition
product of ethylene. Although the formation of ethylidyne on Ru(001) from the dehydrogenation of
ethylene has been studied using high resolution electron energy loss spectroscopy (HREELS) and
reflection absorption infrared spectroscopy (RAIRS) in the past, there is a lack of agreement in the
literature about the mechanism of ethylene decomposition.
In this study, reflection absorption infrared spectroscopy (RAIRS) and temperature
programmed desorption (TPD) were used to characterize and identify the surface intermediates
formed in the thermal decomposition of ethylene (C2H4) on Ru(001). Ethylene is found to adsorb to
the surface in a di-σ bonded complex at 95 K and dehydrogenates to form ethylidyne (CCH3) at
above 150 K. Upon further annealing the crystal to above 300 K, ethylidyne dehydrogenates to
ethynyl (CCH). Annealing to higher than 450 K causes ethynyl to decompose to methylidyne
(CH).The characterization of surface intermediates provides us with more insights into the thermal
decomposition of ethylene on Ru(001), which is essential to reveal the reaction mechanism.
2014 AVS Prairie Chapter Symposium
37
P15
Chemical Analysis of Pd and Ag Interaction with 3C-SiC Thin Films
Rachel Seibert1, Daniel Velazquez1, Jeff Terry1, Kurt Terrani2, Charles Baldwin2, Fred
Montgomery2, Keith Leonard2, John Hunn2, Paul Schuck2, Roger Stoller2, and Stephen Saddow3
Student Poster Award Contestant
1
Illinois Institute of Technology, 2Oak Ridge National Laboratory, 3University of South Florida
The surface interactions of nuclear fission products with the barrier SiC layer of TriStructural Isotropic (TRISO) coated fuel particles limit fuel cell performance. In particular, Pd and
Ag reduce the structural integrity of SiC. An understanding of the reaction mechanisms and kinetics
of these interactions under normal operation as well as accident conditions is critical for the
development of advanced nuclear reactors, but currently is not well understood. This surface
chemistry is examined both in spent TRISO fuel on SiC/Si(111) thin films and compared to
theoretical calculations done by Schuck and Stoller at Oak Ridge National Laboratory [1].
Synchrotron extended X-ray absorption fine structure (EXAFS) spectroscopy measurements were
conducted on the irradiated TRISO fuel pellet to characterize atomic interactions at the Pd K-edge (
24350 eV). The thin films were grown epitaxially via pulsed laser deposition (PLD), as evidenced
by reflection high energy electron diffraction (RHEED) patterns. Pd and Ag were deposited on
separate SiC/Si(111) films in thickness increments from 0.5-5 monolayers. The chemical structure
of the thin films is analyzed using X-ray photoelectron spectroscopy (XPS).
[1] Schuck, P.C. and R.E. Stoller, Ab initio study of the adsorption, migration, clustering, and
reaction of palladium on the surface of silicon carbide. Phys. Rev. B 83, (2011)
2014 AVS Prairie Chapter Symposium
38
P16
Repurposing Blu-ray Movie Discs as Low-cost, Quasi-random
Nanoimprinting Templates for Photon Management
Alexander J. SmithN, Chen WangM, Dongning GuoP, Cheng SunM, Jiaxing HuangN
Student Poster Award Contestant
N
Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive,
Evanston, IL 60208, USA, MDepartment of Mechanical Engineering, Northwestern University, 2145
Sheridan Road, Evanston, IL 60208, PDepartment of Electrical Engineering and Computer Science,
Northwestern University, 2145 Sheridan Road, Evanston, IL 60208
Quasi-random nanostructures are abundant in nature for light manipulation purposes (e.g.,
structural coloration in birds and insets), and have received renewed interest for photon
management in a variety of engineering applications. Typically very expensive fabrication
processes are needed to create quasi-random, subwavelength patterns suitable for light trapping in
photonic devices. Interestingly, such patterns already exist in a mass-produced consumer product.
Here we report repurposing of Blu-ray movie discs as a quasi-random nanoimprinting template.
Regardless of the content, the audio and video compression algorithms convert the data to a highentropy binary sequence before error-control coding and modulation. Eventually, a quasi-random
pattern of pits is generated on the disc, which is found to be surprisingly well suited for photon
management over the solar spectrum. We successfully imprinted the Blu-ray pattern onto the active
layer – and subsequently to the metal electrode – of polymer solar cells, leading to higher
efficiencies.
2014 AVS Prairie Chapter Symposium
39
P17
Fabrication of Pt and Rh Nanoclusters on a Graphene Moiré Pattern
on Cu(111)
Esin Soy1, Zhu Liang1, and Michael Trenary1
Student Poster Award Contestant
1
Department of Chemistry, University of Illinois at Chicago, USA
Formation and growth of Pt and Rh nanoclusters on a graphene covered metal substrate has
been investigated by ultrahigh vacuum scanning tunneling microscopy (UHV-STM). For this
purpose a graphene film was formed on the Cu(111) surface by the decomposition of ethylene at
high temperatures. According to our results, isolated graphene islands were successfully grown on
the Cu surface with different periodicities. Different rotational domains were observed as a result of
weakly coupled Cu and graphene. The most prevalent moiré patterns have periodicities of 2.2, 4 and
6.6 nm with rotational angles of 0° and 8°. Subsequently, nanoclusters were formed at room
temperature on the template of a graphene moiré pattern formed on Cu(111) surface. As confirmed
by the height and size profiles, Rh and Pt clusters display similar planar structures with an average
height of about 0.4 nm and average diameter of about 10 nm (Fig.1). The size and distribution of the
metal clusters on the two types of moiré patterns seem to be different. The clusters on the smaller
moiré pattern show a narrow size distribution in both diameter and height. Additionally, these
nanoclusters are found to be relatively stable and only undergo agglomeration at relatively high
temperatures. These results demonstrate that the metal-C and metal-metal interactions may play a
significant role in the cluster formation and it is possible to fabricate finely dispersed metal
nanoclusters on the moire structure of graphene covered Cu (111).
(a)
(b)
(c)
Fig.1. STM images of (a) graphene moire pattern on Cu (111), (b) Rh nanoclusters, (c) Pt
nanoclusters on graphene covered Cu (111). (Vb=0.7V, It=0.4 nA)
2014 AVS Prairie Chapter Symposium
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P18
Low Temperature Photoluminescence Studies on Sputter Deposited
Cds/Cdte Junctions and Solar Cells
Mohit Tuteja1 , Prakash Koirala2, Julio Soares3, Robert Collins2, Angus Rockett1
Student Poster Award Contestant
1
2
Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801,
Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, 3Frederick-Seitz
Materials Research Laboratory, University of Illinois, Urbana, IL 61801
Device quality CdS/CdTe heterostructures and completed solar cells (~12% efficient) have
been studied using low-temperature photoluminescence (PL) as a function of temperature (82-295
K) and laser excitation power (0.02-2 mW). The CdS/CdTe junctions were grown on transparent
conducting oxide covered soda lime glass using rf-sputter deposition. It was found that the
luminescence shifts from being dominated by sub-gap defect-mediated emission at lower excitation
powers to near band edge excitonic emission at higher excitation powers. The effect of copper (Cu)
used in making back contacts was studied in connection with the CdS/CdTe junction PL. It was
found that the presence of Cu suppresses the sub-band gap PL emissions. This effect was concluded
to be due either to Cu occupying cadmium vacancies (VCd) or forming acceptor complexes with
them. This points to a potential role of Cu in plugging sub-band gap recombination routes and hence
increasing charge separation ability of the device. An energy band diagram is presented indicating
various observed transitions and their possible origins.
2014 AVS Prairie Chapter Symposium
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P19
Assembly and Characterization of Supramolecular Porphyrin
Architectures at Metal Surfaces
Christopher G. Williams and Steven L. Tait
Student Poster Award Contestant
Department of Chemistry, Indiana University
Tuning abundant, first row transition metals to achieve competitive catalytic performance is
a long-standing goal in heterogeneous surface catalysis. The key challenge is to tune selectivity at
the metal center while maintaining high activity. We are investigating prototypical metal-ligand
complexes, including metal porphyrins, which are known to be catalytically active. We developed a
protocol for depositing Cu(II) meso-tetra(4-carboxyphenyl)porphyrin (Cu-TCPP) from a methanol
solution onto the Au/mica surface. Scanning Tunneling Microscopy (STM) is used for molecular
resolution structural characterization and revealed a single monolayer with well-ordered domains
exhibiting square symmetry with a unit cell size of 1.8 nm (Figure 1). The structure is likely driven
by cyclic hydrogen bonding of four carboxylic acid groups. We have also conducted studies of
porphyrins in ultrahigh vacuum (UHV) environments where platinum octaethyl porphyrin (Pt-OEP)
has been vapor deposited onto a Cu(100) surface. We verified the monolayer deposition by Auger
Electron Spectroscopy (AES) and utilized High Resolution Electron Energy Loss Spectroscopy
(HREELS) to identify the vibrational modes of the porphyrin. A key M-N stretch was identified
around 292 cm-1 in the porphyrin, which is of interest for monitoring modifications of the metal
bonding. Ongoing studies will include variation of substituent groups on the porphyrin, and other
ligands, to tune the reactivity of the metals and enable new supramolecular architectures. These
studies will lead to a better understanding of metal-organic complexation at surfaces and to higher
complexity and functionality in surface catalysts.
10 nm
Figure 1: STM image of Cu-TCPP
monolayer deposited from methanol
onto Au/Mica and imaged in air
(Vsample= -0.860 V, Itunneling=74 pA).
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P20
Graphene Oxide Membrane in Water: To Disintegrate or Not to
Disintegrate
Che-Ning Yeh1, Kalyan Raidongia1, Jiaojing Shao1,2, Quan-Hong Yang2, Jiaxing Huang1
Student Poster Award Contestant
1
Northwestern University, 2Tianjin University
Graphene oxide (GO) films have been noted to be highly stable in water, which enables their
membrane applications in solution. However, this is counterintuitive since GO sheets become
negatively charged upon hydration and the membrane should disintegrate due to electrostatic
repulsion. We have now discovered a long overlooked reason responsible for their stability in water.
As expected, neat GO membranes indeed readily disintegrate in water, but the films are stable if
they are crosslinked by multivalent cationic metal contaminants. Such metal contaminants can be
introduced unintentionally during synthesis and processing of GO. The new insight has wide
implications in interpreting the processing - structure - properties relationship of GO and other
lamellar membranes. We also discuss strategies to avoid and mitigate metal contamination, and
demonstrate that this effect can be exploited for synthesizing new membrane materials.
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P21
Atomic Layer Deposition of Metastable β-Fe2O3 via Isomorphic
Epitaxy for Photo-assisted Water Oxidation
Jonathan D. Emery†, Christian M. Schlepütz‡, Peijun Guo§, Shannon C. Riha†, Robert P. H Chang§
and Alex B. F. Martinson†
†
Materials Science Division, Argonne National Laboratory, Argonne, IL, ‡X-ray Science Division,
Argonne National Laboratory, §Department of Materials Science and Engineering, Northwestern
University
Solar-to-hydrogen energy conversion is regarded to be an integral component in the future
renewable energy infrastructure. Photo-assisted electrochemical (PEC) water splitting, in which
water is split into molecular hydrogen and oxygen, remains one of possible routes towards viable
solar-to-hydrogen conversion technology. Of the candidate materials for PEC water splitting
photoanodes, hematite (α-Fe2O3) remains one of the most promising semiconductors for the water
oxidation half-reaction because of its suitable bandgap for solar absorption, its relative terrestrial
abundance and stability in aqueous. However, sluggish water splitting kinetics on the α-Fe2O3
surface and poor charge transport properties continue to limit its application. Other iron oxide
phases are either difficult to synthesize in useful forms or have failed to demonstrate appreciable
photoactivity. Here, we explore bixbyite-phase iron(III) oxide (β-Fe2O3) as an alternative to αFe2O3, and present the epitaxial stabilization of the phase by atomic layer deposition (ALD) on an
isomorphic tin-doped indium oxide (ITO) thin film template.
X-ray diffraction measurements and Raman spectroscopy verify the growth of β-Fe2O3 thin
films with cube-on-cube epitaxy with respect to the low-index [(100), (110), and (111)] epitaxial
ITO/YSZ template. As-grown films are >99% β-Fe2O3 crystalline phase fraction and are
photoactive as deposited. While absorption characteristics and overall PEC activity of the
unoptimized β phase thin films are similar to that of the α phase, bulk β-Fe2O3 has a lower
photocurrent onset potential when measured in the presence of a hole scavenger, as well as a
smaller bandgap, as estimated by Tauc analysis. Ultimately, these properties suggest potential
advantages that β phase photoanodes may hold over conventional hematite in water splitting
efficiency.
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P22
Nanofluidic Ion Transport through Restacked 2D Nanomaterials
Kalyan Raidongia, Jiaxing Huang
Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208
USA
Similar to solids, liquids confined at nanometer length scale exhibit many new properties
and phenomena which are not visible in their bulk counter parts. Investigation of such
nanoscale properties are very important in terms of both scientific understandings and technological
innovations. However, studies on nanometer sized liquids are limited by the expensive and lowthrough-put nanofluidic device fabrication techniques. We recently reported an alternative approach
where unprecedentedly massive arrays of nanochannels are readily formed by restacking 2D
nanomaterials, such as graphene oxide (GO)1. Nanochannels between 2D sheets are successfully
constructed as manifested by nanofluidic phenomena such as surface charge governed ion transport1
for electrolyte concentrations up to 50 mM. Moreover, ion transport through these 2D nanochannel
is also dependent on the shape of the film. For example, a nanofluidic device made from GO film
cut into a triangle shape behaves as an ionic current rectifier. Nanofluidic devices based on
restacked 2D nanomaterials have many distinct advantages such as low cost, facile fabrication, ease
of scaling up to support high ionic currents, and flexibility.
Reference.
1) Nanofluidic Ion Transport through Reconstructed Layered Materials. Kalyan Raidongia, Jiaxing
Huang, J. Am. Chem. Soc. 134, 16528, 2012.
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P23
Low Temperature Synchrotron X-ray Scanning Tunneling
Microscopy (LT-SXSTM)
N. Shirato1, H. Kersell2, C. Preissner1, S.-W. Hla2,3, and V. Rose1,3
1
X-ray Science Division, Argonne National Laboratory, Argonne IL 60439, 2Department of Physics
and Astronomy, Ohio University, Athens, OH 45701, 3Center for Nanoscale Materials, Argonne
National Laboratory, Argonne IL 60439
Low temperature scanning tunneling microscopy (LT-STM) combined with synchrotron
based X-rays provides a new tool to capture chemical interactions and magnetic spin states on
surfaces at high spatial resolution. The technique will drastically increase the spatial resolution, and
it measures chemical and magnetic information along with surface topography. Here, we will
present the current status of the ongoing development of a LT-SXSTM. Compared to our previous
generation microscopes [1], the new system features, i.e. 4 degrees of freedom stages for the sample
and tip alignment with respect to the X-ray beam, in-house developed LabVIEW and MATLAB
based data acquisition and analysis software, 6-axis active vibration isolation system and low
temperature capability down to 4 Kelvin using a liquid Helium flow cryostat.
References
1. M. Cummings et al., Ultramicroscopy 112, 22 (2012).
2014 AVS Prairie Chapter Symposium
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2014 AVS Prairie Chapter Symposium
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Exhibitors at the symposium
We appreciate support from our exhibitors as well as The Department of
Chemistry & Biochemistry at Loyola University Chicago.
Special thanks to Scott Dix and Jeremy Perney for organizing the exhibitors.
2014 AVS Prairie Chapter Symposium
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