OVERVIEW
Funds are requested for the purchase of an Atomic Force Microscope (AFM) integrated with an
inverted light microscope and other accessories for advanced nanometer scale imaging, spectroscopy,
lithography, and manipulation. General-use access to AFM at LU is only available on an old Digital
Instruments (Veeco) Nanoscope III owned and maintained by the Materials Science Department and
Center for Advanced Materials and Nanotechnology (CAMN). This instrument serves as the only shared
AFM and also as the only nanoindenter on campus via a Hysitron Triboscope attachment. Although this
arrangement has served us well for many years, it now places severe limits on our ability to grow into
new areas and to add new users.
In this proposal, we outline plans for obtaining a new AFM from Asylum Research, for use with an
Olympus Total Internal Reflectance Fluorescence (TIRF) microscope and several other key accessories.
Acquisition of this instrument will have a significant impact on research, teaching, and outreach activities
at LU, specifically: (i) significantly improve the capability to characterize surfaces and interfaces, as well
as new biotechnology and nanometer-scale materials; (ii) promote fundamental studies of intermolecular
interactions, self-assembly, and nanofabrication; (iii) help develop new analytical techniques; (iv)
enhance collaborations developing on campus between several academic units such as chemistry, physics,
materials science and chemical engineering; (v) make possible incorporation of the experimental basics of
AFM-based techniques into the undergraduate and graduate curricula; and (vi) motivate new
contributions to K-12 outreach through the existing CAMN ImagiNations remote-microscopy program
that serves 60 Pennsylvania school districts. The instrument will complement existing high-end electron
microscopy instrumentation at LU and will fill a key need of the current research activity of LU faculty.
The instrument will also allow us to bring up to modern standards the nanoscience component of the
curriculum. Acquisition of several key accessories will allow for experiments at the cutting edge of
nanoscience, nanotechnology and biotechnology. Finally, the presence of a new, dedicated AFM will
allow conversion of the existing instrument to a full-time nanoindenter, thereby increasing access and
instrument stability. Purchase of this instrument is crucial to our teaching and research missions.
I. RESEARCH ACTIVITIES
The proposed instrumentation will be used by many faculty and students from the College of Arts and
Sciences and the Rossin College of Engineering and Applied Science, and we highlight here ten primary,
immediate users.
STRUCTURE AND CONTROL OF INTERFACES AT THE NANOSCALE
A. Richard Vinci, Associate Professor of Materials Science and Engineering
Biomimetic Design of Fibrillar Interfaces for Adhesion, Tribology, and Other Surface Properties
“GOALI: Biomimetic design of fibrillar interfaces for adhesion, tribology, and other surface properties”
(Jagota, Vinci, Hallahan, Hui), CMS-0509790, 9/15/2005-8/31/2008, $324,892.
This project, performed in collaboration with Prof. Anand Jagota, aims to develop materials with
fibrillar interfaces that mimic surface structures (setae) in lizards and insects designed for enhanced
adhesion, tribology and other surface properties. A common feature evolved by nature for contact and
universal adhesion against an indeterminate surface, with important variations based on species, is the use
of a hierarchical fibrillar structure with a plate-like spatular terminal element. We are modeling,
designing, fabricating, and testing biomimetic fibrillar structures inspired by this unique architecture.
Lizards and insects often achieve controlled adhesion and tribological surface properties by the use of
fibrillar ‘setal’ structures.1-5 These structures are hierarchical in nature, many microns long, and terminate
in submicron fibrils and sub-100 nm spatula-like plates (Fig. A1, left). It is understood that the
remarkable properties of these interfaces arises because of their structure, not the specific materials
properties. The discrete nature of the fibrils, and their arrangement in an array, is also critical.
1
We
have
been
engaged in theoretical and
experimental studies of
the mechanism of fibrillar
adhesion,
and
in
fabrication of model
structures (Fig. A1 center
and right).6-8 Thus far,
Fig. A1. [left] Near-tip structure of fibrillar setae in O. marmorata (courtesy N. Rizzo,
mechanical measurements
DuPont), [center] fibrillar material fabricated by micromolding using a silicon master,
have consisted of pressing
[right] fibrillar structures fabricated by direct etching of a polymer film.
a large fibrillar array,
consisting of thousands of fibrils, against a glass slide, then pulling off the array while measuring the
resulting forces, typically on the order of a mN. These experiments have been performed using an
inverted optical microscope and a custom-built device for actuation and load measurement. This
combination allows imaging of the decohesion process and “crack front” from below while carrying out
quantitative measurements from above. Fascinating cooperative phenomena have been observed during
the decohesion process, and a paper describing the mechanics of the process is under way. We have been
unable, however, to make similar measurements of individual fibrils or small groups of fibrils due to the
small loads involved. These are critical for separating the cooperative array phenomena from those
inherent in the structural details of individual setae. The MFP-3D-BIO
SPM system is ideal for these experiments. The ability to view the
decohesion process is retained, and force resolution is improved to the
sub-µN scale, sufficient to study adhesion of individual setae. The use of
this instrument will allow us to explore the effects of subtle design
variations and pre-defined surface chemistry of the substrate that are
likely to be essential for understanding and optimizing adhesive
properties.
B. Himanshu Jain, Professor of Materials Science and Engineering
“International Materials Institute: New Functionality in Glasses”, DMR0409588, $3,250,000, 08/01/04 – 07/31/09 (Co-PI: C. Pantano at PSU)
The following are but two examples of a number of activities within
the new NSF-funded International Materials Institute for New
Functionality in Glass. Many users from the IMI have been trained to use
the existing SPM system, and more uses are planned as the IMI grows.
Thus, the installation of a new SPM will serve a large number of users
who are advancing fundamental materials research by performing
research and education projects involving solid state and materials
chemistry, and the design, synthesis, characterization, and processing of
materials. A number of undergraduates, including underrepresented
minority students, are involved with the IMI and will benefit from the
instrument through the REU program.
B1. Photo-Induced Changes in the Surface Morphology of
Chalcogenide Glass Films
Chalogenide glasses are those amorphous solids containing a
chalcogen (a group VI element, typically Se or S). A number of photoinduced phenomena have been identified in this group of materials,
including reversible photodarkening of As-based sulfides and selenides,
and photo-induced phase transformations.9 The latter is the basis for
current DVD recording technology. Other phenomena that show promise
2
Fig. B1. [top] Surface image of
photoinduced topology. [center]
AFM cross-section in the direction
of the electric field. [bottom] AFM
cross-section perpendicular to the
direction of the electric field.
for application in microfabrication are photo-induced fluidity, expansion, and mass transport (as shown in
Fig. B1).10 The first of these has been shown to athermally decrease the viscosity of As 2S3 glass films by
over two orders of magnitude, even at temperatures well below the glass transition temperature. 11 The
second has been used to demonstrate the feasibility of optically forming microlenses. 12 The third has been
used to optically create gratings.13 In all reported cases, the results of the phenomena are welldemonstrated and structural models have been developed,14-16 but the kinetics remain largely a mystery.
We are beginning a study, in collaboration with Prof. Vinci, which will explore the time-dependence of
these related phenomena using AFM. The key to this is the ability to illuminate the specimen and to
measure the accompanying morphological and/or property changes in-situ as they develop.
Surface morphological changes will be measured using surface profiles generated via AFM, similar to
those shown in Fig. B1. Optical access for the stimulating laser must be provided from beneath the
specimen to avoid interference with the mechanical probe. This is very difficult with our existing
equipment. Furthermore, the physical probe must be positioned in such a way as to characterize the
illuminated zone, typically a few micrometers in diameter. Our current AFM equipment does not have the
ability to optically inspect the sample surface to choose the measurement location. The planned study is
possible but unnecessarily difficult to carry out with the current instrument. The combination of inverted
optical microscope integration and integrated AFM presented by the proposed instrument will enable us
to perform all of the desired studies, determining for the first time the kinetics of several related photoinduced phenomena. The proposed instrument is equipped with optical filters that will prevent
interference between the instrument laser and the illuminating laser.
B2. Nano lithography and photostructuring of chalcogenide glass films
a
b
Fig. B2. Scanning electron micrographs of As35S65
nano-gratings patterned with e-beam and then
etched. (a) shortest dwell time, 0 stage tilt, and
(b) longest dwell time, 40 stage tilt.
Chalcogenide glasses, generally soluble in alkaline
solvents, become more resistant to etching in amine-based
solvents after exposure to high energy electrons (30 keV).
We have used this characteristic for fabricating structures
that are suitable for nanolithography, writing nano-gratings
with varying point spacing, line pitch, and electron dose
(Fig. B2). The finest structures that have been created in our
arsenic sulfide films have lines with widths of 27 nm,
separation of 7 nm, and heights from 80-250 nm. As the
line pitch decreases, the best resolved spacing between the
lines decreases until the lines blend into each other, much
before the e-beam overlaps. A careful high resolution
imaging system is crucial for the optimization of writing
and etching parameters that will yield the resolution one
expects from a 1-nm beam. This capability currently exists,
but increased access to a shared, user-friendly instrument
will speed development and allow increased involvement by
undergraduates, many of whom participate in the IMI. As
many are underrepresented minority students, this will
automatically aid diversity efforts also.
C. Steven L. Regen, University Distinguished Professor, Professor of Chemistry
Porous and Glued Langmuir-Blodgett Membranes. “Pore-Forming Amphiphiles”, NSF, $428,190,
2/15/2004-1/31/2007; “Porous and Glued Langmuir-Blodgett Membranes”, DOE-Office of Science,
$390,000, 8/15/2005-6/14/2008.
The need for improved methods of separating gases is increasingly apparent. One important example
is the separation of H2 from CO2. In particular, current efforts that are being aimed at moving the Unites
3
States towards a hydrogen fuel economy face many major challenges, one of which is the development of
more energy-efficient methods for purifying H2 that is produced from reforming processes.
This program focuses on the creation of new classes of ultrathin membranes that are expected to lead to
highly energy-efficient methods of separating H2 from CO2, and other gas mixtures that are of industrial
importance; e.g., H2/N2, O2/N2, etc. Specifically, this research involves the synthesis and characterization
of single, porous and ionically cross-linked (i.e., "glued") Langmuir-Blodgett (LB) bilayers that are
expected to show permeation characteristics that place them above the "upper bound" for H 2/CO2, due to
molecular sieving.17-26 This upper bound represents a theoretical line that defines the maximum H 2/CO2
permeation selectivity and maximum H2 permeability that is expected for solution-diffusion mechanisms
of transport. Although these studies lie at the basic science level, recent advances in continuous LB film
deposition should allow for the large-scale synthesis and manufacturing of such membranes. In a broader
context, this research will
CH3
significantly
expand
the
chemistry of glued LB bilayers,
which should encourage other
O
researchers to reexamine the
CH2
6
possibility of exploiting the
nonlinear optical, piezoelectric,
C
HON
NH2
pyroelectric, semiconducting,
sensing and barrier properties
of LB films from a practical
Fig.C1. A calix[6]arene bearing n-butyl “tails” and amidoxime “head” groups.
standpoint.
Space-filling models appearing to the right, showing a side and top view.
Fig. C1 shows a calix[6]arene-based
surfactant that is typical of the type that we are
CH
CH
currently exploring. Scheme 1 shows a new
H
CH
O
approach toward gluing that we are pursuing,
N
O
CH
H
O
6
which is based on hydrogen bonding. The
CH
n
6
characterization of glued LB membranes relies
HO
H
N
N
on a combination of gas permeation selectivity
H
HO
H
N
N
H
measurements,
X-ray
photoelectron
H
N
O
H
spectroscopy, water contact angles, ellipsometric
n
measurements, infrared spectroscopy, and AFM.
In very recent studies, we have found that AFM was of critical importance in characterizing the
rearrangement of non-glued calix[6]arene monolayers in air to bilayer structures. 17 Although the
capabilities needed for this work are within the scope of the existing shared AFM, scheduling is often
difficult due to the heavy user load. Extending the AFM capabilities at Lehigh should have an immediate
impact on our efforts in building fundamental understanding of the structure, properties, and dynamics of
these films.
Scheme 1
CH3
3
2 n
2 n
2
2
D. Sabrina Jedlicka, Assistant Professor of Materials Science and Engineering
Peptide Structure and Cellular Function at the Biointerface, Lehigh University start-up funds
Novel materials designed to mimic or replace the traditional cell culture environment are a
promising step towards developing implantable devices and improving upon existing biomaterials.
Peptide modified silica rationally designed to induce solid-state signaling has been shown to offer a
controllable biological interface28 that is capable of inducing differential cellular development 27.
However, several fundamental questions surround the development and eventual translation of these
materials into the in vivo environment.
As cells adhere to a cell culture surface or biological material, the cell encounters the
biointerface, which is a mixed modality environment of both soluble components, as well as a gel-like
viscous layer of extracellular proteins. The proteins are known to activate a variety of downstream
4
signaling pathways that affect the fate and function
of the adherent cell. ECM proteins, such as
laminin, contain numerous integrin binding sites,
and the presentation of specific binding sites is
critical to the protein function and eventually the
response of cellular material. We have shown that
short bioactive peptides can be used to direct cell
function to an extent28 however, the performance
of the materials is not sufficient to push a
population of neural stem cells into a fully mature
neuronal fate. Improvement to the materials
requires a fundamental understanding of the
Figure D1. Surface Topography of Peptide Film. Fluid
biophysical properties of the peptides at the surface
cell AFM height images of thin film produced from peptide
of the material, including secondary structure,
silane and TMOS precursors. Arrow indicates potential
binding site presentation, and ultimately the
peptide “clustering”, not seen on unmodified TMOS
derived thin films.
adhesive nature of the cells.
The availability of integrin ligands is critical. Fluid cell AFM is an ideal technique to study ligand
presentation, as it allows for maintenance of the native structural and biochemical nature of the
interaction. AFM tips will be derivatized with appropriate commercial integrin receptors, allowing for
identification of ligand availability based on phase shift. We have previously imaged the peptide modified
materials under fluid cell AFM (Figure D1, instrument located at Purdue University), and have observed
the existence of potential peptide “clustering” on thin film modified silica. Tip derivatization and the
closed fluid cell environment availability at Lehigh will greatly enhance these efforts and provide the
opportunity to study detailed biophysical phenomena of peptide modified surfaces, as well as other
biomaterials.
A second proposed goal is to investigate the strength of cellular binding. The two-dimensional
character of most biomaterials leads to stringent requirements on the part of the cell to adhere in a manner
that is not typically found in nature. The strength of adhesion is therefore a likely factor in the ability of
cells to fully differentiate and function as a mature population. Using AFM to measure adhesive forces at
points along cells of interest will provide detailed information about biointerface interactions and
adhesive nature. Comparing strength of adhesion and desired cellular processes to basic material
properties will provide a key to rational design of biomaterials and allow for tailoring of material
properties to suit a particular biological application.
The MFP-3D BIO SPM system is ideal for these experiments. The cells and materials may be
visualized with optical microscopy, allowing for sample identification and microscopic imaging. The use
of this instrument will allow for exploration of binding site availability and allow for rational materials
design based on peptide folding. In addition, the ability to tailor adhesion properties of cells based on
function will allow for further engineering of cell culture substrates for stem cells and other cell biology.
NANOPARTICLES: PROPERTIES, SELF-ASSEMBLY, AND PATTERNING
E. Tianbo Liu, Assistant Professor of Chemistry
Mechanical Strength of a New Type of Inorganic Membranes. "CAREER: Hydrophilic Macroionic
Solutions”, CHE-0545983, 4/1/2006-3/31/2011.
Soluble inorganic ions are expected to distribute homogeneously in dilute solutions. However, we
recently discovered that this widely accepted concept, although correct for small ions, might not hold for
some giant, highly soluble, fully hydrophilic inorganic macro-ions. These macro-ions29-34 (usually welldefined polyoxometalate molecular clusters), are highly soluble in polar solvents, but they usually do not
only exist as discrete ions even in dilute solutions, obviously contradicting our commonly accepted
knowledge regarding inorganic solutes. Instead, they tend to self-associate into hollow, spherical, singlelayer, vesicle-like “blackberry”-type structures even in dilute solutions (Fig. E1).35-44 Results from laser
5
light scattering, TEM (transmission electron microscopy), SEM, and
AFM studies suggest that the macro-ionic solutions behave differently
from simple ionic solutions and colloidal suspensions and could
represent a previously missing intermediate region linking these two
areas.
One of the most intriguing features of the blackberries is that
although formed by inorganic species, they behave like “soft” biomembrane-like organic materials: their walls are very thin but fairly Fig. E1. Spherical vesicle-like
robust. A high-resolution TEM study showed that a {Mo154} “blackberry” structure (90-nm in
formed by over 1150 {Mo154}
blackberry burst and collapsed during the drying process on a surface size)
“giant wheel” POMs in aqueous
as a consequence of losing water and looked very similar to a broken solution, as determined by various
lipid membrane. This could be due to the existence of water molecules techniques, cited from ref.[52].
between adjacent macro-ions on the surface. Water molecules tend to
be much more viscous in a tiny confined environment and act as a “glue” to stick macro-ions together.
The concept of an increase in viscosity of water in a confined nano-environment will be tested by
experiments on “nano-rheology”, in which the AFM tip is brought into contact with the macro-ions and
then the frequency range is swept with nanometer-sized excitation of the tip. Recording amplitude and
phase response of the tip is fully analogous to macroscopic rheology experiments. Access to an
instrument with programmable nanomanipulation and user-defined external signals is key to
implementing such experiments.
The mechanical strength of vesicle membranes is known to be important for their applications. The
properties of the thin blackberry wall, a type of novel inorganic membrane, still remain unclear. AFM can
be very useful for this study. As shown in Fig. E2, a study on {Mo72Fe30} blackberries (dia. ~30-50 nm)
on a Au surface by AFM indicated that their height was only about 10 nm, suggesting that the shape of
blackberries had been distorted due to the interaction with the solid surface. Moreover, their height
continued to decrease, as a result of losing internal water. These results suggest that the mechanical
strength of blackberries could be high.39
We plan to test the
mechanical strength of the
blackberries
and
to
understand how it changes
with external conditions by
using AFM tips to tap the
same structure with different
forces
while
monitoring
changes of the horizontal
shape and topography. We
Fig. E2. (left) A TEM study on a broken {Mo154} blackberry on a carbon film clearly
will also carry out direct
indicates the wrinkle feature and high contrast around the edge that is very similar to
biomembranes. (middle and right) An AFM study shows that the blackberries change
nanomechanical experiments
their morphology on a surface just like a bag of water, and their height continues to
on individual blackberries.
decrease with time due to the loss of internal water. Data are from ref. [50].
Furthermore, we also plan to
explore the effect of macro-ionic charge density, which should affect the mechanical strength of the
blackberries. Force-distance measurements with chemically modified tips under controlled ionic strength
will allow us to establish experimentally the surface charge density of individual blackberries. The
information we will gather from these studies will be critical to understand how to make stronger
blackberries, or how to soften/break them, if necessary. Such results will help to choose blackberry
systems for different applications such as drug carriers, nano-containers, and reactors.
F. Christopher J. Kiely, Professor of Materials Science and Engineering
Nanowire and Nanopattern Fabrication by the Sintering of Self-Assembled Nanoparticle Arrays:
Sintering Studies of Lines, Rafts and Metamaterials. NER Grant DMI-0304180 (Co-PI: M.P. Harmer)
6
$90,000, 7/2003-12/2004; NSF Nanomanufacturing Grant CMMI-0457602 (Co-PI: M.P. Harmer),
$400,000, 4/2005-4/2009.
Research is being carried out to assess the potential usefulness of a new nanomanufacturing method;
namely, the controlled sintering of self-assembled arrays of ligand stabilized metal nanoparticles to form
nanowires and complex 2-D nanopatterns for eventual nanoelectronic applications. Our work aims to
establish a basic understanding of how (i) particle size, (ii) particle array configuration, (iii) substrate
identity, and (iv) the method of ligand destabilization affect the nature of the nanowire or nanopattern
formed.45-47 Ordered two-dimensional arrays of nanoparticles are formed relatively easily by the
controlled evaporation of a drop of colloidal solution of nanoparticles on a suitable substrate. However,
the fabrication of linear chains of nanoparticles on the other hand is much more difficult, requiring either
chemical or physical templating of the substrate prior to nanoparticle deposition. The proposed AFM can
be used to great effect in this research for (i) chemical templating by using the instrument in dip-pen
lithography mode or (ii) physical templating by scraping nanoscopic grooves into a spin coated polymer
layer. A particularly challenging but intriguing motif to fabricate would be 1-D chains of nanoparticles in
which the nanoparticle identity alternates regularly along the length of the string (e.g. Au/Ag/Au/Ag).
This could then be subsequently sintered into a wire that has a periodic chemical superlattice along its
length. It is highly likely that sophisticated chemical recognition between the ligand stabilized Ag and Au
nanoparticles and chemically distinct alternating ‘ink dots’ pre-drawn on the substrate using the AFM will
be required to achieve this goal. The new instrument incorporates comprehensive nanolithography and
manipulation capabilities using the “The MicroAngelo” feature within the MFP-3D System.
G. Bruce Koel, Professor of Chemistry
Nanomanipulation and Layered Nanofabrication
The objectives of the research in this area are the fabrication of functional nanostructures by directed
manipulation. Koel was one of the four founding members of USC’s Laboratory for Molecular Robotics
(LMR) in Fall of 1994, a highly interdisciplinary team from chemistry, physics, materials science, and
computer science. The most recent funding of this work from NSF was “NIRT: Nanorobotics” (9/1/02 –
8/31/06), with co-PIs A.A.G. Requicha and M.E. Thompson, at USC. Research in the LMR tackled and
provided reliable and accurate methods for directed manipulation of nanoparticles and structures by using
the tip of a SPM as a sensory robot in ambient air or in liquids and at room temperature.48-52 The team had
to learn to compensate for the many spatial uncertainties involved in the manipulation, e.g. thermal drift
or piezoelectric creep and hysteresis, build customized software for the SPM controller, and address
issues for the automated assembly of nanoparticle patterns. We developed the expertise required for
precise assembly of nanoparticle patterns under ambient conditions, including fabrication of singleelectron transistors (SETs), and chemical sensors based on SETs, linking and manipulating linked 2D
structures,53 and building 3D nanostructures,54 including by a process that we invented called layered
nanofabrication (LNF).55, 56 We manipulated a range of nanoparticles, nanorods,57 nanowires, and built
nanowaveguides58 and other nanodevice prototypes that may be used in more complex structures and
patterns required by nanoelectromechanical systems (NEMS).
While self-assembly is the primary tool for “bottom-up” fabrication, directed assembly by
nanomanipulation can play an important role in fundamental experiments on the nanoscale behavior of
matter and be an important component in the fabrication of prototypes, “one-of” devices for testing and
evaluation, especially when combined with self-assembly strategies. Manipulation software developed in
the LMR was unique at the time and served its purpose. However, directed manipulation can now be
readily accomplished using the Asylum lithography software. This avoids the need for a number of our
previous software fixes to account for drift and hysteresis and search for the desired particle. In fact, the
non-contact/contact mode switching of the Asylum AFM during a line scan is something that we were
never able to accomplish in a simple manner in the LMR. Much exciting work remains to be done, and
two experiments are outlined below. Acquisition of the proposed AFM is crucial for this work to proceed.
7
G1. Thermal stability of Au nanoparticle patterns
Methods are needed for the assembly of nanoscale
components (e.g., nanoparticles) into more complex structures.
One approach is thermal sintering. This idea extends our
previous work joining gold nanoparticles by using di-thiols
and connecting them by electroless deposition of additional
gold.59 We have already demonstrated this idea by joining
latex nanoparticles simply by heating them, as shown in Fig.
G1.60 Now, we would like to extend these studies to more
robust metal nanoparticles such as Au. We plan to position Au
Fig. G1. 3D-rendered image of the effects of
nanoparticles with sizes of 5-20 nm by pushing them on a
sintering on a closely packed structure (left)
surface with the tip of an AFM and then study their behavior
to a stable island (right). AFM crossduring heating. We will use the AFM to characterize the
sectional analysis show that the peak height
expected changes and probe for the mechanisms that operate,
of the structure remained constant at 100 nm.
distinguishing between particle melting, coalescence, and
particle sintering by particle diffusion or atomic evaporation and condensation coarsening mechanisms.
G2. Layered nanofabrication using self-assembled monolayers (SAMs) and bilayers
Designed fabrication of structures on a nanometer scale often requires progress in the efficiency and
control in deposition of self-assembled monolayers, especially in our LNF approach. We plan studies of
the embedding of gold nanoparticles in layers of OTS (octadecyltrichlorosilane) and MOSUD (methyl11-dimethylmonochlorosilyl-undecanoate) deposited on a SiO2 surface. AFM will be used in ex-situ
studies of the formation of SAMs, including self-replicating OTS and MOSUD bilayers. AFM analysis of
the Au nanoparticles after several layer-by-layer growth cycles will reveal a decrease in apparent height
and roughness according to the number of deposited layers. We seek strategies for improved control of
growth exclusively on the substrate, with none on the particle (but conformal to the particle), and the
controllable, stepwise growth of flat, multilayer films that will eventually produce a high-quality,
planarized nanoparticle-containing surface.
PROPERTIES AND APPLICATIONS OF CARBON NANOTUBE SYSTEMS
H. Slava V. Rotkin, Assistant Professor of Physics
Nanophotonics and nano-optoelectronics with nanotubes. “High Resolution Characterization of
Carbon Nanotube Materials,” NASA, $62,507, 6/30/06-6/29/08. “Physics of Light-to-Electric-Signal
Conversion in Carbon Nanotubes: Novel Route for
Making Nanoscale Optoelectronics Devices, Army
Research Laboratory”, $129,075, 5/1/06-4/30/07.
In the course of two ongoing projects on studying
electronic and photoelectric properties of CNTs we
identified a critical area where the new instrument
would be not only useful to stitch the characterization
data from in-situ TEM transport and ex-situ photoelectric measurements, but it will also allow a series of
new experiments and resolve the ambiguity due to the
samples used in TEM and optics are entirely different.
SWNT bandstructure is very sensitive to
symmetry breaking and environmental effects61-63,
which makes the engineering of electronic properties
possible without any doping64-66. The bandgap opening/closing and Fermi velocity renormalization may
Fig. H1. Use of SPM tip for local gating the CNT on the
SiO2 substrate. Strong focusing of the electric field at the
apex of the tip breaks the NT symmetry and induces the
bandgap [Rotkin and Hess, 2004]. Inset: Microphotograph of the existing SPM-TEM holder (W. Muschok).
8
be induced by local electric fields provided by a local gating of an SPM tip 67 (Fig. H1). The locally
controllable variation of the NT electronic properties by changing the Hamiltonian of the system –
“mesoscopic bandgap engineering” – may be, at least in principle, translated into a transistor function.67
However, weak screening in one-dimensional (1D) systems results in unusual charge distribution along
the transistor channel,68, 69 strong Coulomb scattering70 and ultimately large sensitivity of 1D field effect
transistors (FETs) to a probing setup, impurities and environment. A custom-made Nanofactory-Gatan
SPM-TEM stage (Fig. H1, inset) has been installed recently for use inside a TEM. It will allow to apply
high local electric bias to investigate CNT bandgap modulation with immediate control of the tube
chirality and radius. However, the TEM samples may require preliminary scans outside the TEM to prove
good electrical connectivity and the proper placement of nano-objects with respect to the electrodes. The
new AFM instrument will allow ex-situ characterization of the TEM samples or twin samples on
semiconductor substrates (in an existing collaboration with Prof. Kiely in CAMN). Requested conductive
AFM setup will be an ideal tool for such routine preliminary scans prior to in-situ experiments.
A transport measurement provides indirect information about the bandgap, while the optical study
could resolve the ambiguity. We have recently built a low-noise low-current photoelectric setup.
Combining both optical and transport measurements with a microscopic resolution is not feasible at this
time. In addition, a gas/fluid environment cannot be easily applied to the sample. Both of these functions
can be achieved with the requested AFM. We propose to use the new AFM equipment to perform
transport, electrical gating and photoelectric experiments on CNT/nanowire samples.
We will apply a controlled gating thanks to the open source capability of the requested AFM. Our
external hardware (Keithley SCS 4200, inset of Fig. H2) is calibrated for high-accuracy sourcing down to
10 fA and 10 microV range. Using confocal microscope we will be able to scan the sample with the laser
probe while taking the photo-conductivity data to be compared with the scanning conductive probe
microscopy under the constant illumination. Cross-correlation of these two techniques will give us
fidelity about the bandgaps of particular CNTs (CNT ropes) with or without light, with or without
environment, in varying temperature range. The new AFM setup will be a primarily tool for fine
experiments to determine CNT bandgaps and optical response of the individual tubes.
The conductive probe capability of the instrument will allow us to obtain the electric potential
mapping of the samples. For example, we can identify the charged impurities that exist at the surface of
the SWNT and on the substrate and may considerably change, hide and even invert the effects of the local
electric fields we will be looking for. The strong field of a pair of nearby impurities may dissect the
nanotube channel and make a quantum dot, which will result in interesting charge localization, a
Coulomb blockade effect, and/or resonant transport. The Scanning Gate technique has been proven to be
the best method to study charge impurity levels in the CNT samples. We will use the new AFM equipment
for detecting the amount of Coulomb impurities and for fundamental studies of the electronic structure of
the nanotube itself as it appears via Coulomb blockade and/or resonant tunneling.
I. Anand Jagota, Prof. of Chemical Engineering, Director of the Bioengineering and Life Sci. Program.
Behavior of Carbon Nanotube (CNT)-DNA Hybrids: Structure, Fundamentals of Interaction with
Electric Field and Surfaces, and Nano-patterning with CNT-DNA “NIRT-GOALI: Solution-Based
Dispersion, Sorting, and Placement of Carbon Nanotubes” (Co-PIs: Kiely, Rotkin), CMS-0609050,
$1,249,960, 8/2006 - 7/2010.
Since their discovery in 1991,71 CNTs have been studied intensively because of their unique and
remarkable structure, and resulting mechanical and electrical properties. They have been shown to be
promising materials for a wide variety of applications, for example, as (i) reinforcements for composite
materials,72 (ii) conducting elements,73 field emitters for displays,74 semiconducting materials for
nanoelectronic devices,75-78 biosensors,79-82 and (iii) vehicles for localized heat therapy or ligand delivery
to a cell.83 Many of these properties derive from their unique 1D structure and, for single-walled CNTs
(SWNTs), due to the precise but sensitive dependence of electronic properties on chirality. 84 Recently
discovered hybrids of carbon nanotubes with DNA85-87 have proven to be very effective in advancing our
9
ability to manipulate CNTs by acting as dispersion agents, enabling sorting, and by providing a technique
for controlled placement on a substrate. Scanning probe techniques have been and will continue to be
critically important for this research in a number of ways.
I1. Structure of the hybrid. Direct imaging has been used both for routine characterization of carbon
nanotube length distributions to more detailed studies of the structure of the hybrid material. For the
former, there really is no other technique that compares in ease of use. For the latter, our best
confirmation of the predicted structure of the DNA-CNT hybrid still comes from careful imaging (Fig. I1).
We also propose to use the force-measurement capabilities of the new instrument along with cantilevers
with CNT tips to make direct measurements of the interaction between the tip and surface-bound singlestranded DNA (in a silane SAM). Separation of carbon nanotubes using DNA-CNT hybrids depends on
the modulation of the electric field of charges on the DNA backbone by the nanotube core. 86, 88 We
propose to measure the electric field near DNA-CNT deposited on a Si wafer under water.
I2. Controlled placement of carbon nanotubes on a substrate. We use a recently discovered87
technique for controlled placement of carbon nanotubes on a substrate. In this technique a drop of dilute
aqueous dispersion of DNA-CNT is placed on a hydrophobic Si wafer or glass substrate for several
minutes. When the drop is washed away subsequently, it leaves an ordered array of carbon nanotubes on
the substrate (Fig. I2). We have proposed that aligned deposition is mediated by the formation of a quasi2D liquid crystal sheet a few nanometers away from the surface. This occurs because of a local
concentration of DNA-CNT due to a secondary minimum in its interaction potential with the surface.
Currently we have indirect evidence that supports our model, such as the dependence of deposition
kinetics on concentration, time, pH, and ionic strength of the solution. More suggestive is the fact that the
pattern of deposited DNA-CNT can be systematically controlled by external conditions, such as pinning
by surface electrodes; this process can be modeled by the equations of liquid crystal elasticity.
Fig. I1. (a) Molecular model of single-stranded DNA wrapped around a (10,0) carbon nanotube (b) Atomic force microscopy
image of DNA-CNT hybrid and its model.78
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We propose to use a
combination of scanning probe and
optical microscopy to study directly
the liquid crystal layer. These
experiments include (i) direct
imaging of the liquid crystal sheet
by exciting the fluorescence of the
carbon nanotubes, or by tagging the
DNA with a suitable fluorophore,
(ii) attempts to image the liquid
crystal layer in situ, and (iii) using
the AFM tip to probe or apply a
potential near the surface.
By
starting under conditions where
natural deposition is inhibited, we
will attempt to use a biased AFM tip
to ‘write’ well-aligned CNT
patterns. Use of the TIRF setup is
critical to decouple visualization
and application of potential bias in
these nano-lithography studies.
Fig. I2. (a) Schematic drawing of an experiment demonstrating control of
nanotube orientation via external electrodes, (b) Predictions of a continuum
theory of liquid crystals is in very good quantitative agreement with
experiments and can form the basis for predictive design and control of local
aligned orientation. (c) AFM micrographs of aligned carbon nanotubes at
different locations.78
J. Dmitri Vezenov, Assistant Professor of Chemistry
Mechano-Optical Properties of Carbon Nanotubes for Photovoltaic Applications
Semiconducting carbon nanotubes are direct-gap one dimensional nanostructures, and their optical
properties has lead to extensive exploration of their potential applications in nanometer-sized
optoelectronics.89 Both light-emitting electrically driven CNT devices90 and photogenerated currents in
CNTs91 have been reported. Photoconductivity has been studied in single CNT devices 92 as well as in
nanotubes films (mostly nanotube-polymer composites),91, 93-95 although there are some arguments
regarding the nature of the photoresponse.93 CNTs can sustain large deformations, thus, mechanical
deformation of carbon nanotubes may provide a direct way of tuning the energy band gap 96 in a rational
way to achieve superior performance of photovoltaic or electrochemical cells that rely on photon energies
available in the solar spectrum. Photomechanical actuation has already been reported for CNT-polymer
films, although a different mechanism is responsible for observed effects.94, 97
The goal of this project is to perform experiments on tunable CNT-based photovoltaics and
photoelectrochemical cells. To develop fundamental understanding of coupling between mechanical and
optical properties in these devices, we will characterize the photoconductivity of individual CNTs
undergoing tip-induced deformation. Combining conductive AFM capabilities with simultaneous optical
excitation and mechanical nano-manipulation will allow us to measure directly the dependence of the
mechano-optical response on CNT strain and structure. A conductive AFM tip applying both bias and
force (either laterally or pushing into an elastic substrate) serves as a probe for photoconductivity. The
capability to image the nanotubes and then perform (i) preprogrammed manipulation (applying a preset
bending force/angle or load at a specific location along the nanotube), (ii) optical excitation, and (iii)
conductance measurements will be available in the new instrument and is unique for the proposed type of
the experiments. The results on the basic mechano-optical behavior of the CNTs will then be used to
design photoelectrodes on flexible substrates for tunable performance.
Results from Prior NSF Support
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“Acquisition of a High Performance SEM for Research into the Nanostructure of Materials”, NSF-MRI
Grant # DMR-0521218, J.A. Eades, C.J. Kiely, H.M. Chan, M.P. Harmer and R.P. Vinci, (Sept. 05-Aug.
07), $613,340.
This grant was awarded to purchase a new Hitachi 4300 variable pressure scanning electron
microscope. It is a Schottky source instrument with superior imaging performance that can operate in
variable pressure, low voltage and environmental modes. It is equipped with a state-of-the-art integrated
EDAX-TSL energy dispersive X-ray spectroscopy (XEDS) and electron back-scatter diffraction (EBSD)
system. The instrument was installed during the summer of 2006, and users were trained throughout the
second half of the year. The instrument is now fully operational and is being used to solve a wide variety
of materials problems. It is used very heavily by a wide cross section of the university as well as external
partners, and has had the desirable effect of offloading use of our dual-beam Focused Ion Beam system
considerably, allowing that instrument to be more effectively used for micromachining work.
II. DESCRIPTION OF INSTRUMENTATION AND NEEDS
University Needs
Advanced SPM equipment at Lehigh is limited to use within the labs of three of the PIs: Koel (UHV
STM), Vezenov (AFM), and Jagota (AFM). These instruments are equipped with custom modifications
specific to the projects for which they were purchased that make general use by others unfeasible. Also,
the time allotment on these instruments is consumed to a large degree by their designated research
projects (~70 % at these initial stages of the projects, and will likely increase in the future). The intense
use of the instruments for major projects also limits their availability for other routine and advanced uses
in these researchers’ own groups. The only general-use AFM instrument on campus is an old Digital
Instruments (Veeco) Nanoscope III, circa the mid 1990’s, that is owned and maintained by the Materials
Science Department and the Center for Advanced Materials and Nanotechnology (CAMN) under the
direction of PI Vinci. It has a Hysitron Triboscope nanoindenter on a small-sample MM-AFM platform
as an attachment. This AFM system is very heavily used, has somewhat outdated capabilities (reflecting
its age), lacks flexibility in the design of experiments (e.g., the command code is not open source), has no
nano-manipulation/lithography capabilities, and does not allow for simultaneous optical observation.
There is no capability for the study of biological materials in-situ. The performance of the instrument is
poor by current standards and does not meet the needs of the research described above. This situation
severely limits the nature and quality of research that can be conducted.
The existing AFM situation at Lehigh also negatively affects our ability to satisfy our educational
mission. We have no cutting-edge instrument that can be used to educate and train undergraduate and
graduate students in what is arguably the most significant tool for advancement of new knowledge in
science and engineering in recent times -- scanning probe microscopy. While we incorporate scientific
breakthroughs made possible by AFM into our curriculum, the ability to carry out remote demonstration
of AFM operation, as well as the inclusion of the experimental basics of AFM within undergraduate
laboratory courses, will strengthen the educational impact on future scientists and engineers. Likewise,
the remote demonstration and operation capability, along with the high resolution and intuitive nature of
AFM images, will strengthen our ability to participate in K-12 outreach to Pennsylvania schools.
Our choice of an AFM was motivated by the extremely versatile nature of modern AFM instruments,
a desire to complement the world-class assembly of electron microscopes in CAMN, and the specifics of
research foci of newly hired faculty members (and planned hires in the near future).
Proposed Instrumentation
Asylum Research has introduced an instrument that is ideally suited for accomplishing our research
and teaching objectives. Their MFP-3D-BIO-OLY AFM, for use with an Olympus inverted light
microscope, is a high-performance AFM that is designed specifically for a wide variety of chemical,
biological, and materials science applications. One can carry out high-resolution imaging and follow
dynamic events in liquid and controlled ambient environments, make force measurements of hardness or
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elasticity or determining intra- and intermolecular forces, and perform nanomanipulation and
nanolithography by contacting the surface under controlled force, cutting and manipulating biomolecules
and nm-scale objects (CNTs or semiconducting nanowires), and mechanically pushing nanoparticles.
Specifically, the AFM requested herein is a state-of-the-art instrument that has the following features:
1)
2)
3)
4)
Provides 3-axis closed-loop operation, low noise (<0.3 nm), and excellent linearity;
Capable of all established imaging modes (contact, intermittent contact or “tapping”, and lift modes);
Operation in any environment except vacuum (ambient, controlled humidity, liquid, flow-through);
Sample stage includes temperature control modules in two temperatures ranges, which are configured
for either biological (up to 80º C) or materials (up to 360º C) related problems;
5) Conductive AFM module allows for application of a bias between AFM tips and samples, thus
enabling transport measurements, as well as studies of surface potential;
6) An extensive module has been developed for force spectroscopy experiments and analysis,
incorporating user-defined conditions and acquisition of force profiles at user-defined locations on the
sample. A digital-access module provides access to and triggering of external signals;
7) Instrument software interface is “open source” to enable scripting and analysis by the user, and the
instrument controller is user-programmable;
8) Nanolithography and nanomanipulation capabilities are “built-in” with user-defined parameters;
The MFP-3D-BIO model is designed to operate on an inverted microscope base, which can add
several other, complementary powerful microscopy techniques such as FRET (Förster resonance energy
transfer), TIRF (Total Internal Reflectance Fluorescence), or confocal microscopy. Several projects will
require simultaneous optical stimulation or observation of the sample, and we have requested a TIRFmounted option. The open-source platform of the Asylum AFM further insures seamless integration of
data acquisition from the two microscopes. Furthermore, the open-source platform and Windows XP
compatibility makes low-cost remote operation possible. The IGOR PRO computing environment chosen
as a software platform by Asylum Research has several built-in features that make the instrument
particularly attractive for rapid prototyping of cyber-enabled AFM capabilities: (i) experiment notebooks
can be saved in HTML format; (ii) built-in commands (e.g., user-programmable) support transfers of files
and directories over the Internet (via ftp protocol); (iii) a url can be opened directly from the command
line, and (iv) IGOR PRO can communicate with other programs via DDE protocol (Windows) and can be
used as a WWW CGI-Bin Server. These features, together with a built-in programming interface, should
enable us to design a set of custom programs for efficient documentation and sharing of results.
While the research of the nine faculty members described here clearly requires routine SPM imaging,
multiple advanced capabilities are needed: 1) three projects (E, I1, I2) require force spectroscopy
capabilities; 2) five projects (C, D, E, I1, I2) need operation under controlled liquid environment; 3) four
projects (A, B1, I2, J) rely on simultaneous optical excitation/observation, including that under TIRF
conditions; 4) six projects (A, B1, E, G, I2, J) use advanced nanomanipulation/nanolithography
capabilities; 5) three projects (A, B1, E) seek expanded access to existing nanoindentation capability and
to new nanomechanical capability; and 6) five projects (A, E, G, I2, J) will benefit from customized
software code for instrument control and user-supplied external signals. The features required of the
proposed AFM have also been described above in the research activities section that detailed specific
research projects. Thus, the MFP-3D-BIO (or an improved model offered by Asylum Research or by
other manufacturers) will enable us to carry out state-of-the-art research along with the education and
training functions of several Departments at Lehigh University.
Accessories and Options
Most manufacturers provide instruments as “basic” systems, and list optional items needed for low-noise
or advanced operation. Several additional budgetary items, therefore, are requested in the proposal:
1) Installation and training is purchased separately, but it is best to rely on trained factory personnel;
2) A vibration isolation table and acoustic noise enclosure must be included to achieve that quoted
resolution and noise specifications of the SPM;
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3) The closed fluid cell, environmental controller, and temperature-controlled stage are required for
operation in controlled-fluid environments. The ability to work in liquids is absolutely essential for
many chemical and biological samples, and we plan studies of these type of samples as apparent from
the description of the research projects;
4) A digital-access module is needed to synchronize AFM and other user designed experiments;
5) For low light-level light microscopy (such as single molecule, or single nanotube experiments), a
digital camera with an electron multiplying (EM) CCD is required to capture optical images.
These items will be supplied directly by the company delivering the instrument. The inverted optical
microscope will be fitted with an AFM stage by Asylum Research and can be delivered either directly by
the microscope manufacturer or through Asylum Research. The digital camera will be obtained from a
separate manufacturer (rather than an SPM company) to reduce the cost.
III. IMPACT OF INFRASTRUCTURE PROJECTS
Hands-on Student Learning.
Direct instruction in the use of SPM equipment is an important aspect of this proposal. A number of
undergraduates have been trained to use the existing AFM, but the ease of use and greater accessibility
offered by the Asylum instrument will enable expansion of this effort. Prof. Koel teaches a course entitled
“Surface Chemistry” (LU catalog Chem 488), and gives lectures in “Strategies for Nanocharacterization”
(LU catalog MatSci 356/456), that includes formalized instruction in AFM techniques and applications.
Prof. Vezenov is teaching a graduate level course “Force Spectroscopy in Chemistry and Biology”, in
which he would like to add laboratory experiments on quantitative force spectroscopy and
nanomanipulation. The course emphasizes chemical and biological systems. In addition, experiences with
AFM should very nicely fit into activities in the long-standing Center for Emeritus Scientists in Academic
Research (CESAR) program within Chemistry, which offers undergraduate science and engineering
majors a unique opportunity to do research under the supervision of a retired industrial scientist. The
program directly impacts 6-8 students each semester and summer, encouraging them to pursue
industrial/pharmaceutical careers in Chemistry, Biochemistry, and Biological Sciences.
Students taking a one-week course during the summer at LU that focuses on AFM will also directly
benefit. Koel and Vinci are lecturers for the course “Scanning Probe Microscopy: From Fundamentals to
Advanced Applications” that is offered each summer, with 10-20 yearly participants. This course
provides an understanding of the concepts, instrumentation, and applications of the rapidly expanding
field of scanning probe microscopy. AFM and STM are covered extensively, along with advanced
techniques for imaging and measuring electronic, magnetic and mechanical properties. The theory of
operation, imaging, and spectroscopy are addressed, with attention paid to instrumental artifacts and
methods to avoid them. Applications in both the physical and biological sciences and engineering are
covered during the lectures and lab demonstrations.
Indirect instruction via remote operation of the proposed AFM opens up new possibilities for use as a
teaching instrument. We will develop new and appropriate Cyber infrastructure for: (i) remote operation,
(ii) class-room demonstrations and instruction aids, and (iii) recording and sharing of data gathered with
this instrument. One example would be developing remote control of this equipment via the internet. As
an example of the success of this approach, Prof. Vezenov has tested successfully remote control
operation of the remote desktop configuration over Lehigh University’s VPN (virtual private network).
Since AFM software by the Asylum Research is Windows XP based, the remote operation of the
instrument should be straightforward from any PC (laptop) capable of running Lehigh’s VPN independent
of location of the PC (with available high speed internet connection). This low-cost approach will enable
us to institute the use of remotely controlled demonstration AFM experiments in the Lehigh Microscopy
School, public schools outreach program, and graduate level courses that Vezenov and Koel are teaching.
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Outreach with remote-operation capability
LU’s CAMN includes the Materials Instructional Technology Lab (MITL), a fully staffed, state-ofthe-art educational technology facility whose purpose is to enhance the research and outreach activities of
the Center. CAMN and MITL are funded primarily by the State of Pennsylvania (“PA Materials Research
Science and Engineering Center” funded by the PA Ben Franklin Technology Development Authority at
$2,700,000 for 5 years ending in 2008) and the National Science Foundation (a subcontract for $300,000
over 6 years from Carnegie Mellon University under the National Science Foundation award for the
project titled "MRSEC: Carnegie Mellon University Materials Research Science and Engineering
Center”). Currently, MITL staff members are responsible for directing an outreach program called the
“ImagiNations Program” that brings remote operation of an environmental scanning electron microscope
(E-SEM) into the K-12 classroom. We plan to include the remotely-operated SPM in this effort,
expanding the types of phenomena that can be imaged, and opening up new pedagogical possibilities by
incorporating fluid environments and the inherent quantitative aspects of SPM technology.
MITL personnel work closely with Lehigh’s College of Education and Library Technology Services
to provide K-20 access to science tools through Web-based scientific inquiries. We are currently
partnered with four State of Pennsylvania intermediate units representing over 60 school districts. A
number of teachers from these districts have been trained to work with the remote-operation E-SEM
software. Students submit items that interest them —pieces of dead insects, coins, or whatever else they
like — and the items are loaded into the SEM. Items representing ongoing LU research projects are also
loaded. The students are then able to observe the items at high magnification from their own classrooms.
This mode of operation has worked very well for the SEM, so it should also work for the AFM.
The ImagiNations Website (http://www.lehigh.edu/imaginations) provides another mode for
introducing K-12 students to microscopy and nanotechnology. Pre-prepared scale and surface area
animations are available for the students’ interaction, along with highly magnified images. This program
was highlighted nationally in 2005 as one of the most innovative applications for Internet2. Recently, we
have been invited to collaborate with NASA’s Virtual Microscope Project to supply SEM images, which
will be included in an image database for virtual manipulation. The image database, including nanoscale,
characterized materials, will be useful as an educational tool for K-20 students and working professionals.
The remotely operated SPM will merge seamlessly into the existing outreach programs, leveraging
the personnel and connections already in place, while complementing the SEM capabilities. An advantage
that SPM has over SEM is the ability to chemically and physically manipulate the material of study. Also,
the ability to work in liquids opens up additional possibilities for incorporation of the images into
chemistry curricula – something that is not currently a significant component of the ImagiNations effort.
The ability to bring a molecular and biological aspect to this program will also be unique for an SPM
instrument. A third notable advantage of SPM over SEM is the quantitative nature of the data. This makes
it possible for the students to carry out “investigations” that use mathematical skills. The acquisition of a
new AFM will catalyze the implementation of SPM images in ImagiNations and other outreach efforts.
IV. MANAGEMENT PLAN
The AFM will be housed in the Microscopy Center within the Center for Advanced Materials and
Nanotechnology (CAMN) at Lehigh University and will be a central facility, accessible to all University
researchers. Specifically, it will reside in a room that has just been renovated to house the existing shareduse AFM and the new UHV-STM-XPS instrument of one of the senior personnel (Koel). In the period
1997-2003 more than $900k of non-Federal (i.e. Lehigh Univ., State and Industry) funding was spent in
the Microscopy Center upgrading peripheral instrumentation (e.g. EDS detectors, specimen stages,
computers), room infrastructure and specimen preparation equipment. In addition, DOD funding was
obtained to purchase an FEI Dual-Beam Focused Ion Beam (FIB) system and NSF funding supported the
purchase of a new Hitachi SEM. The proposed AFM will be located in this environment and operated
within the same management system. Since the environment is already good, it is anticipated that little
change will be needed to make the space suitable for the new microscope.
15
The research instruments in the Microscopy Center (including 3 SEMs, 2 TEMs, 2 STEMs, 1 FIB, 1
electron microprobe, and 1 AFM) are under the direction of Prof. Chris Kiely and the day-to-day
operation is managed by a research engineer, David Ackland, with support from William Mushock and
Alfred Miller. Dr. Miller is a UHV equipment specialist with responsibility for the Scienta ESCA 300
facility (the only XPS instrument of its kind in the U.S.) and the existing VEECO AFM. He provides
basic maintenance services and user training, purchases consumable items, and processes user charges.
The costs associated with equipment servicing, as well as a portion of the salaries of the aforementioned
support staff who maintain the instruments, is recovered through charges to research grants and teaching
budgets. The new AFM will be operated in the same way, as a user facility. Dr. Miller will assume
responsibilities for the new AFM in (i) training students and researchers in the proper use of the
instrument, (ii) interpretation of the data, and (iii) assistance with design and implementation of researchspecific modes and experiments. Access to the instrument will be made available as widely as possible.
Time will be allocated (subject to the user being appropriately trained) on a first-come, first-served basis.
Prof. Koel is Dr. Miller’s current supervisor, and he will continue in this role to provide administrative
and technical supervision of the new AFM instrument.
Modern AFM equipment has an ease of use and wide applicability similar to that of an SEM. In the
last five years our SEMs have been used by students and faculty from 10 different departments and
centers at Lehigh, 20 corporations, 2 national laboratories, and 9 universities. The current AFM has
external users from Lehigh, other university partners, and industry partners as well, but not yet at the level
of the SEMs. We anticipate that the availability of a user-friendly, modern AFM will greatly increase the
user base in the same way that SEM equipment renewal has generated new users.
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