News & Highlights
News from the Center.
Partnering with a Charter School to Reach At-Risk Students
Nugget :: CCMR Staff :: Jun 27, 2007
The Cornell Center for Materials Research (CCMR) has been developing hands-on activities to interest students in science and technology for over a decade. To bring these resources to some of New York City’s most at-risk students, the CCMR has partnered with the Harlem Children’s Zone (HCZ) — a pioneering, non-profit community-based organization that works to enhance the quality of life for children and families in central Harlem. more.
JumpStart helps Small Businesses
Nugget :: CCMR Staff :: Jun 27, 2007
High-tech companies are often faced with unexpected technical challenges that have to be solved before a product can be brought to market. Such problems can be deadly for small companies, which rarely have the resources to operate a large R&D lab staffed by technical experts. more.
Frozen Silicon “Trees” tell Story of Melting
Nugget :: CCMR Staff :: Jun 27, 2007
Scientists have long predicted that some crystals don’t melt all at once. Instead, the topmost layer of atoms melts before the other layers, creating a liquid that is only one atom thick. Seeing this liquid is fiendishly difficult, though. Researchers at Cornell have verified this prediction using a clever trick — they watch the melting of ultraflat silicon crystals. The silicon crystal is heated to a temperature just below its normal melting point, then cooled. more.
Developing a “Lab-on-a-Particle”
Nugget :: CCMR Staff :: May 14, 2007
Cornell researchers have developed nanoscale particles that can be loaded with molecular “cargo,” such as a drug or other therapeutic agent. When delivered to their target, the nanoscale particles release their cargo and then sense the reaction to the release. Thesemultifunctional nanoparticles form the basis of a “Lab-on-a-Particle” — nanoscale structures that are capable of performing multiple tasks. more.
Switchable Molecules for the World’s Smallest Switch
Nugget :: CCMR Staff :: May 14, 2007
Some molecules conduct electricity; others don’t. Researchers at Cornell are working to make the world’s smallest switch out of a single molecule. To do this, they have created a molecule that can be switched from conducting to non-conducting with a flash of light. In its “normal” state, the molecule is orange and doesn’t conduct electricity. more.
Helping 4th Grade Students meet the New York State Standards
Nugget :: CCMR Staff :: May 6, 2007
Local teachers came to the CCMR with a problem. The New York State Learning Standards require 4th grade students to learn that energy and matter interact through forces that result in changes of motion. More importantly, 4th graders must learn to design and carry out experiments to illustrate this, and then organize and explain their findings in simple charts. more.
Beating the World’s Smallest Drum
Nugget :: CCMR Staff :: May 1, 2007
Scientists at Cornell have reached the ultimate limit in miniaturization by making a drum with a single-atom-thick drumhead. In their device, a single atomic sheet of graphite (a so-called graphene sheet) is stretched across a silicon trench. By shining a laser on the surface, the scientists can show that only one atomic layer of graphite is present. more.
CCMR reaches out to New York City teachers
Nugget :: CCMR Staff :: Jan 24, 2007
This March, the CCMR Educational Programs Office will coordinate with the Weill Cornell Medical College to work with New York City middle school physical science and high school physics teachers on improving their classrooms and curriculum. This event is a special one for educational outreach at Cornell because it involves the cooperation of several different offices on the main campus along with the Weill Graduate School of Medical Sciences of Cornell University in New York City. more.
Using Templates to Conquer Disorder
Nugget :: CCMR Staff :: Dec 5, 2006
Engineers have long dreamed of making inexpensive electronics out of thin films of organic materials, such as plastics. This dream has been met by a significant challenge —disorder. Organic films are typically composed of tiny crystals. Although each crystal is perfect, the molecules in one crystal are aligned in a different direction than those in the next crystal. This random order impedes the flow of electricity and leads to poor performance. more.
Engineering Structural Colors Using Nonspherical Building Blocks
Nugget :: CCMR Staff :: Nov 23, 2006
Structural colors, not originating from pigments but rather from the interaction of light with microscopic features, can be observed in many living systems including butterfly wings, spines of marine animals, peacock feathers, and the brilliant blue facial skin of primates. Examination of the microscopic structure of these tissues reveals the attributes of a photonic crystal system –fine-scale periodic arrays which serve as color-specific mirrors. more.
Better Electronics from Silicon Corrals
Nugget :: CCMR Staff :: Nov 15, 2006
Today's electronic devices are so small and so sensitive that even atomic‐scale defects can degrade their performance. Controlling individual atoms on a silicon chip would seem to be a Herculean task; however, we have developed a simple method of "corraling" these defects and improving the performance of electronic devices. The image at right shows a silicon wafer with a single corral. more.
MicroWorld hits the Road!
Nugget :: CCMR Staff :: Nov 8, 2006
For 10 years, rural elementary school teachers have come to Cornell to participate in MicroWorld—a one-day hands-on workshop in optical microscopy. This year, MicroWorld hit the road and traveled 200 miles to work with urban teachers in New York City. more.
Tight Nanostrings Have Better Tone
Nugget :: CCMR Staff :: Nov 8, 2006
Stradivarius violins and our new nanostrings have one thing in common —they both produce very high quality tones (or vibrations). In physics, the quality of a string is a measure of the number of times the string will vibrate after being plucked. A high quality string, such as the one on a violin, will ring long after it is plucked. more.
Is It A Solid or a Liquid?
Nugget :: CCMR Staff :: Nov 5, 2006
Every schoolchild learns that there are three states of matter —solid, liquid and gas —but we have recently synthesized a new class of "furry" nanoparticles that have the properties of both solids and liquids. The nanoparticles have a solid core, which can be made of silica (sand) or other inorganic materials, that anchors a corona of longer, ionic molecules as sketched at right. Even in the absence of solvent, these nanoparticles flow like a liquid. more.
Do not bend, fold or mutilate
Nugget :: CCMR Staff :: Nov 2, 2006
Carbon nanotubes are hollow tubes made from single sheets of carbon atoms. Along the length of the tube they can be excellent electrical conductors, and they are also the stiffest known material. However, just like a drinking straw, they can be easily deformed or pinched in a radial direction. Attaching electrical contacts to the tube has always proved challenging —some contacts are good, others a thousand times worse. more.
CCMR Seed Grows Into a Company
Nugget :: CCMR Staff :: Jan 27, 2006
Using NSF Seed funding, Chemistry Professor Geoffrey Coates, a member of the Cornell Center for Materials Research (CCMR), discovered a catalyst system that provides unprecedented activity and control in the synthesis of biodegradable polymers using carbon dioxide — a known greenhouse gas — as a starting material. This increased control will allow chemists to tailor the properties of these materials, known as aliphatic polycarbonates, to specific applications. more.
CCMR's Newest Program for High School Teachers
Nugget :: CCMR Staff :: Jan 19, 2006
CCMR's newest program for high school teachers made its debut in the summer of 2005 to rave reviews from the teachers themselves. The program, called the CCMR Institute for Chemistry Teachers (CICT), is a unique opportunity for teacher professional development. Through lectures by Cornell faculty, hands-on laboratory activities and research facility tours, teachers gain an appreciation for modern chemistry and learn about recent advances in the field. more.
Inner City High School Students Investigate Time in Chemistry and Physics
Nugget :: CCMR Staff :: Dec 17, 2005
What is university life like? Students in inner city high schools often have a hard time answering this question. To gain first-hand knowledge, students at McKinley Vocational High School travelled to Cornell to tour the facilities, meet students and explore the campus. During their visit, the students performed hands-on physics and chemistry experiments that explored time and frequency with CCMR faculty. more.
CAREER: Variable-Temperature Electric Force and Magnetic Resonance Force Microscopy of Organic Electronic Materials
Nugget :: John A. Marohn (Dept of Chemistry), Erik M. Muller (Dept of Physics) :: Jun 28, 2005
Research Objective: We are trying to gain a better microscopic understanding of organic electronic materials - carbon based molecules that behave like semiconductors. The reason to study these materials is that they might one day be used for cheap mass-produced electronics, sensors, and solar cells. Conduction of charge in these materials in not well understood. Approach: We image trapped charge directly in these materials using electric force microscopy. more.
Silicon Carbide-based mesoporous ceramics
Nugget :: CCMR Staff :: Apr 1, 2005
Nanostructured polymer-inorganic hybrid materials offer enormous scientific and technological promise in areas ranging from microelectronics to the life sciences. Block copolymers are particularly interesting as structure directing agents since they allow precise control of the hybrid and, after thermal processing, of ceramic morphology. We have prepared the first ordered mesoporous high-temperature (non-oxide type) ceramic material. more.
A Micromechanical FM Radio
Nugget :: CCMR Staff :: Apr 1, 2005
We have shown that very small mechanical resonators (like tiny tuning forks) can replace electrical oscillators in radio and cell phone applications, making these electronic systems even smaller. To illustrate the potential of our structures, an FM radio receiver was fabricated from one of our devices. more.
Science and the next Stradivarius?
Nugget :: CCMR Staff :: Apr 1, 2005
The CCMR Small Business Outreach Program seeks to address materials issues vital to small manufacturers while building a relationship on which to leverage greater research opportunities. Allred & Associates of Auburn, New York recently received a small exploratory grant from CCMR to work with Prof. Alan Zehnder (T&AM) to characterize the company's new carbon fiber products using the CCMR shared experimental facilities. more.
New Versatile Polymers, from hard to soft to elastic
Nugget :: CCMR Staff :: Apr 1, 2005
A series of new polymerization catalysts have been invented and found to be very effective in the synthesis of new block copolymers. These catalysts have the potential to make new forms of polypropylene, a commonly used polymer in many consumer and industrial products. The new polymers can be synthesized to have a wider set of properties than ordinary polypropylene, from hard to soft to elastic. more.
Plucking the World's Smallest String
Nugget :: CCMR Staff :: Apr 1, 2005
Carbon nanotubes are hollow tubes made from single sheets of carbon atoms. In addition to being the stiffest material known, carbon nanotubes are extremely light and extremely small. Because of this, carbon nanotubes are potentially the ultimate building block for nanoscale mechanical devices, such as ultrasmall chemical detectors. Advances in this area have been stymied by a simple problem — the small size of nanotubes makes them difficult to work with. more.
Interactions Between Magnets and Buckyballs
Nugget :: CCMR Staff :: Apr 1, 2005
As the size of electronic devices is reduced to the nanometer scale, effects arising from quantum-mechanical interactions between electrons can be examined in direct ways that were previously impossible. more.
Bright & Stable Core-Shell Fluorescent Silica Nanoparticles
Nugget :: CCMR Staff :: Apr 1, 2005
A new class of highly fluorescent, stable nano-particles has been invented with potential applications in many technologies, including photonics and bio-imaging. Many millions of these with almost identical diameters can be produced in a simple process, enabling many applications that will be inexpensive. Nano Letters 5 (2005), 113-117. more.
High quality organic films for transistor applications
Nugget :: CCMR Staff :: Apr 1, 2005
How many layers of organic molecules does it take to build a flexible transistor? Synchrotron X-ray diffraction and atomic force microscopy were used to understand the structure of very thin pentacene films and relate that to the transistor's characteristics. Surprisingly, only 5 to 6 molecular layers are needed to obtain the best performance. more.
Center and Community Join to Reach Underserved Youth
Nugget :: CCMR Staff :: Apr 1, 2005
CCMR reaches out to underserved youth through the community-based Ithaca Youth Bureau (IYB). Located in Ithaca, NY, the Youth Bureau serves primarily African-American and low socioeconomic local children. In summer 2004, CCMR began offering hands-on science activities to students from the IYB summer camp. Professors Geoff Coates and Dotsevi Sogah (Chemistry Dept. ) launched the first series of programs. more.
Understanding how small is nano
Nugget :: John Sinnott :: Apr 1, 2004
False color image of the 3-D profile of a segment of a patterned aluminum line on silicon taken using CCMR's phase shift microscope. The pattern is shown in the inset photo. The line was made via thermal vapor deposition, photo-lithography and etching by students in a freshman introductory nanotechnology course at Cornell. The image is also used in a high school outreach lab that teaches how resistance depends on both material and geometry. more.
Big science helps little fish
Nugget :: Patrick Govang, Paul Corriveau :: Apr 1, 2004
Composite polymer strands, lines and cords are difficult to design because the properties depend in a complex way on the individual properties of the components and the interactions between the components. A CCMR engineering faculty member developed a novel apparatus to study the properties of such composites (bending stiffness, fatigue, wear and friction) to allow the experimental optimization of composite formulations. more.
Devices bridge research and applications
Nugget :: Jeevak Parpia, Melissa Hines :: Apr 1, 2004
The true potential of MEMS and NEMS devices can only be realized once they can be integrated into existing silicon based circuitry. The devices at left show a 50W resistor that can be used to thermally drive a high-Q radio-frequency (rf) resonator. The invention of these devices [CRF-patent appl. more.
Teachers show gains through outreach
Nugget :: Kevin Dilley :: Apr 1, 2004
CCMR is collaborating with Professors Elizabeth Shiner Klein and Gail Tooker of the State University of New York (SUNY) Cortland Education Department to develop a quantitative research evaluation of CCMR's Research Experience for Teachers (RET) programs. The initial evaluation process has gotten underway collecting data from a sample of five middle and high-school teachers who participated in the 2003 RET summer program. more.
Reaching out to El Salvador
Nugget :: Nev Singhota :: Apr 1, 2004
CCMR has recently expanded its educational programs beyond U. S. borders. Spurred by physics graduate student Christopher Deufel, a frequent volunteer in CCMR outreach programs, Citigroup Foundation awarded a grant for to bring CCMR-developed science education modules to El Salvador. CCMR provided additional funding through a donor to enable Mr. Deufel to travel to and within El Salvador. The program was initiated in January 2004. As of March 2004, Mr. more.
Improved switching performance of Si based integrated optical devices
Nugget :: Michal Lipson, Michael Spencer :: Apr 1, 2004
A unique device structure in SiC was designed and simulated. This simulation predicted switching speeds on the order of 10 picoseconds, for a 20x33um2 device operated at 12V. This device would represent a significant increase in switching performance of Si based integrated optical devices. In addition these devices, which are based on resonant techniques, can be realized with an extremely small footprint. Fig. 1 shows the design of our simulated structure. more.
Structured Colloids
Nugget :: Abraham Stroock, Fernando Escobedo :: Apr 1, 2004
A new microfluidic reactor for controlling chemistry and mechanical agitation in a colloidal dispersion has been developed at Cornell. An associated new Monte Carlo method for studying the thermodynamics of non-spherical particles predicts an unusual liquid crystalline phase with "cubatic" order such that the particles have fluid-like mobility but net orientation along three orthogonal axes. more.
A Little Wax Improves Nanoscale Tuning Forks
Nugget :: Source: "Controlling energy dissipation and stability of micromechanical silicon resonators with self-assembled monolayers," Joshua A. Henry, Yu Wang, and Melissa A. Hines, Appl. Phys. Lett. 84, 1765-7 (2004). :: Apr 1, 2004
What do cell phones, quartz watches, and FM radios all have in common? They all need a stable frequency source, or internal clock, to operate. As every musician knows, the simplest frequency source is a tuning fork . a piece of metal that vibrates at the same pitch (or frequency) every time it is struck. In principle, tuning forks could be used to simplify cell phones and other devices; however, these high frequency applications would require nanoscale tuning forks. more.
Ultra-Small Memory Devices for Silicon Electronics
Nugget :: Sandip Tiwari :: Apr 1, 2004
The devices on silicon chips that run computers continue to shrink, but we can foresee that the current designs will not work when they become much smaller. For example, small differences in the electrical charge stored in individual silicon based memory devices leads to such different device behavior that they cannot work together. more.
Bright nanoparticles that don't fade or blink
Nugget :: Uli Wiesner :: Apr 1, 2004
Nanometer-scale materials hold great promise for use in enabling new technological breakthroughs in the area of photonics. We have developed fluorescent silica nanoparticles with a novel design concept (CU dots) for use in photonic materials and devices. They consist of a core containing multiple organic fluorophores surrounded by a dense silica shell with sizes down to the 10 nm regime. more.
Designing atomic step patterns on Surfaces: Step pinning and wrap around . Effect of a pillar at the center of a pit
Nugget :: John (Jack) Blakely :: Apr 1, 2004
Pillars inside depressions pin the steps as they move across the surface due to evaporation-dominated step motion; the steps can wrap around the pillar and break away, resulting in an effective increase of the pillar height by one atomic layer. This allows the pillar, whose top atomic layers are disappearing, to persist over longer annealing times. more.
Liquid Nanoparticles
Nugget :: Dotsevi Sogah, Emmanuel Giannelis :: Apr 1, 2004
Nanoparticles of many materials have been prepared in the laboratory and all are very fine powders in pure form. We have discovered that nano-particles below a certain size can be transformed into pure liquids by attaching the right molecules to the surface of each particle. The addition of a second, normally liquid substance like water or alcohol is not needed. The nano-liquids will enable new applications of nano-particles to materials technologies. more.
Dimension 3100 Scanning Probe Microscope
Nugget :: CCMR Staff :: Sep 12, 2003
Shared surface characterization facility. This microscope provides a platform for conventional atomic force microscopy (AFM) along with a number of additional imaging techniques, including electric force microscopy (EFM), magnetic force microscopy (MFM) and scanning tunneling microscopy (STM). The microscope is located in a central facility, is accessible at all hours to trained users and can be reserved via a web-based scheduling program. more.
Nano-transistors Sensitive to Vibrations in a Single Molecule
Nugget :: Ralph, Sethna and McEuen, in collaboration with Soldatov (Harvard) :: Apr 1, 2003
Cornell researchers have pioneered techniques that have enabled transistors to be made from single molecules. Understanding such devices is an important challenge, because their behavior differs from conventional transistors in a number of ways. One significant difference is that molecules can vibrate and move. more.
New Silicon Nano-transistor Designs
Nugget :: Tiwari :: Apr 1, 2003
Current transistor technology is approaching limits that prevent smaller devices from being manufactured. A new approach to this problem has been pioneered at Cornell. The approach is based on manipulating the storage of charge in naturally-occurring states at the interface of a nanoscale silicon nitride layer incorporated into transistor devices. In present technologies, logic and memory are usually carried out with separate types of devices. more.
Stronger Plastics
Nugget :: Giannelis :: Apr 1, 2003
Plastics (polymers) are often reinforced by blending other materials, such as glass fibers or clays, into the polymer to make a composite material. Cornell researchers have previously shown that dispersing layered silicates (clays) as atomically thin layers in polymers enhances the strength and lowers the flammability of polymers. A remaining challenge was to develop a process for dispersing clays in polymers that require high temperature processing, such as polycarbonates. more.
Improving the Adhesion of Metal Films to Glass
Nugget :: Baker, Pang, Wang and Hui :: Apr 1, 2003
Thin metal films are deposited on glass for use in flat panel computer displays, mirrors, optical components, etc. However, metal films are prone to peeling away from the glass. Cornell scientists have developed a new method for measuring the adhesion of metal films to glass and exploited that method to show that impurities in the film have a dramatic effect on the adhesion. more.
Nano-scale Imaging of Insulators Using Electric Currents?
Nugget :: Umbach and Blakely :: Apr 1, 2003
Usually, insulators do not allow electrical currents to flow. Yet Cornell engineers have pioneered a technology that allows the surfaces of insulators to do just that. Why would that be interesting? When an engineer needs to determine the degree of smoothness of a solid surface at atomic scales, the choice is between atomic force microscopy (AFM) and scanning tunneling microscopy (STM). more.
Growing Crystals One Atomic Layer at a Time
Nugget :: Dale, Fleet, Wang, Suzuki and Brock :: Apr 1, 2003
Based on the rapid evolution of electronic and optical devices to smaller dimensions, one can readily foresee the day when many materials will need to be made from stacks of atomically thin layers of different composition. Developing the tools to control and probe the growth process of such stacks on the atomistic scale in real time is a formidable challenge. more.
Shake Those Diamonds
Nugget :: Sekaric, Parpia, and Craighead, Feygelson, Houston and Butler :: Apr 1, 2003
Diamond is the hardest material known. In collaboration with the Naval Research Laboratory, CCMR scientists have shown that it also can be used to make a "xylophone-like" resonator attain frequencies approaching those used in cell phone communications. A unique web-like design will enable optical readout at high frequencies. Understanding the factors that limit the frequency and the purity of the vibrations in very small mechanical resonators is the focus of this group. more.
Ordered Molecular Layers in Sensors and Light Emitting Devices
Nugget :: Abruña, Houston, Malliaras, Blasini, Smilgies, Slinker, Flores and Lee :: Apr 1, 2003
Designer molecules that can be electrically stimulated to emit light can be synthesized to also be sensitive to TNT and related molecules. CCMR researchers have created globular molecules that pack efficiently on surfaces and thereby increase their light emission or sensitivity to TNT and related molecules. The researchers used X-ray reflectivity to monitor and optimize the packing process of individual molecules as they form very thin films on various surfaces. more.
Growth of Ultra-Thin Organic Films for Electrical Devices
Nugget :: Malliaras, Mayer and Kazimirov, in collaboration with Headrick (Vermont) :: Apr 1, 2003
Imagine electronic circuits on paper, plastic, or cloth! Organic semiconductors, like pentacene, can make this happen because they can be deposited on practically any surface. Researchers at CCMR are investigating the arrangement of pentacene molecules on various surfaces. By using X-ray radiation, it is possible to "see" how the first few layers of pentacene molecules arrange themselves on particular surfaces. more.
New Ways to Make Biodegradable Polymers
Nugget :: Lee, Qin and Coates :: Apr 1, 2003
The synthesis and proper disposal of most polymers pose important environmental challenges. Therefore, the synthesis of biodegradable polymers as well as reducing the use of non-renewable resources is important. CCMR researchers have developed new catalysts for the synthesis of polymers from carbon dioxide. CO2 is an ideal synthetic feedstock since it is abundant, inexpensive, nontoxic, and nonflammable. more.
Porous Magnets: Magnetic Fe-containing Ordered Thin Films
Nugget :: Wiesner and Gruner :: Apr 1, 2003
Magnetic materials are well known for many technologically important applications. The new porous magnetic materials developed at CCMR may enable precision medical tests for early stage disease detection. For the first time, a new process for the creation of porous patterned iron oxide containing thin films has been developed. more.
Switchable Photonic Materials
Nugget :: Ober, Gruner and Thomas :: Apr 1, 2003
Optical materials are the basis of the telecommunications revolution. Photonic bandgap materials can be used in such applications to switch and direct optical signals. Oriented block copolymers are an important new class of optical material that possess a tunable photonic bandgap, are easy to process and can create conformal coatings. more.
Marvelous Magnets
Nugget :: Educational Programs Director, Nev Singhota :: Apr 1, 2003
As a large, interdisciplinary NSF Materials Center, CCMR offers the surrounding community a wide variety of programs and opportunities to learn about our scientific and engineering activities. During the past year, we have offered 30 separate educational outreach programs reaching approximately 36 undergraduates, 850 K-12 students, 110 parents of school children, 225 schoolteachers, and 81,000 upstate New York newspaper readers, and numerous community members. more.
Professional Development Day
Nugget :: Educational Programs Director, Nev Singhota :: Apr 1, 2003
The CCMR Educational Programs Office offers educational and training programs for K-12 science teachers. Faculty, postdoctoral associates, graduate students, and staff work with teachers in local school districts to provide teacher training. In 2003, CCMR collaborated with the Ithaca City School District to present hands-on learning modules to 140 K-5 teachers. more.
Research Experience for Teachers (RET)
Nugget :: Educational Programs Director, Nev Singhota :: Apr 1, 2003
Mary Kay Hickey, high school chemistry and biology teacher, participated in the CCMR Research Experience for Teachers (RET) program during the summer of 2002. She worked with Professor D. Tyler McQuade and his group in looking at a number of fluorescent compounds in order to characterize their properties for future use in the lab and see if they can spot any interesting interactions that might have application in sensors. As a result of her research with Professor McQuade, Ms. more.
Molecular Transistors
Nugget :: Héctor Abruña, Paul McEuen and Dan Ralph. :: Jan 1, 2002
Molecular devices might enable the manipulation of single electrons on the smallest possible device length scales. A cross disciplinary group at Cornell has demonstrated for the first time a transistor device that reaches the ultimate limit in which an electron hops on and off a single atom between two contacts. This has been achieved by nanofabricating gold (Au) electrodes separated by a very narrow gap. more.
Nanostructured Polymer- Ceramic Composites
Nugget :: Uli Wiesner and Sol Gruner :: Jan 1, 2002
For the first time, ceramic nano-dots, nano-wires, nano-sheets, nano-networks and nano-channels can all be synthesized by the same process. The process utilizes special polymers, called block co-polymers, which were known to solidify into a variety of organized nanoscale regions, whose dimensions can be controlled by changing the length of the polymer. more.
Making Waves, Nanostyle
Nugget :: Kit Umbach, Cary Allen, Matt Daniels and Jack Blakely. :: Jan 1, 2002
Bombarding SiO2 surfaces with high speed atoms or ions at glancing angles produces quasi-periodic nanoscale surface corrugations or ripples. This unusual effect can be explained by changes in the surface flow properties (viscosity) of the SiO2 under bombardment. more.
Unraveling nucleation and growth of copper films on TiN, TaN and SiO2
Nugget :: Paul Ma, Todd Schroeder and Jim Engstrom. :: Jan 1, 2002
Copper is quickly replacing aluminum in microelectronic devices. In these devices, it is important to encapsulate the Cu metal wires not only for electrical isolation purposes, but also to prevent the (detrimental) diffusion of Cu into other parts of the device. This is achieved by using thin impermeable layers that are referred to as "diffusion barriers. more.
Island density increases during sputter deposition
Nugget :: Josh Pomeroy, Oana Malis, Jim Sethna, and Joel Brock :: Jan 1, 2002
Major advances in communication technology have been made possible using techniques such as sputter deposition. This technique, for example, is used to fabricate the thin films in the read heads on a hard disk drive. In sputter deposition, the depositing atoms collide with the surface with high energies, resulting in smoother films, but how this occurs has remained a mystery. more.
Pumping Up Tiny Oscillations
Nugget :: Lidija Sekaric, Maxim Zalalutdinov, Jane Wang, Harold Craighead, Jeevak Parpia and Alan Zehnder :: Jan 1, 2002
The vibration of nanomechanical resonators (very small "tuning forks") is highly damped by the presence of air. We have shown that special methods can restore the vibrations by adding a little energy to the resonator during the part of the period where the resonator is at its maximum excursion from equilibrium. This is rather like lightly pushing a child's swing when it is at the top of its arc. more.
Carbon helps grow larger pentacene grains
Nugget :: Michele Swiggers, Chris Johnson and George Malliaras. :: Jan 1, 2002
Imagine electronic circuits on paper, plastic, or even cloth! Organic semiconductors, like pentacene, can make this happen because they can be deposited on any surface. Researchers at the Cornell Center for Materials Research recently found a new way to improve the quality of pentacene films. By just depositing a thin layer of carbon between pentacene and the substrate, a ten fold increase in the size of the pentacene grains was achieved. more.
CCMR & Corning: Interaction with Industry
Nugget :: Senior researchers include: Neil Ashcroft, Dieter Ast, Shefford Baker, Jack Blakely, Rüdiger Dieckmann, James Engstrom, John Silcox, Chris Umbach. Collaborators from Corning, Inc. include Ellison, Felner and Coiler. :: Jan 1, 2002
Research 1 micron x 1 micron AFM image of an ion irradiated surface of a Corning flat panel display glass (aluminoborosilicate). The dominant repeat spacing of this large area self organized quasi-periodic surface modulation is ~ 70nm. Surface was Argon ion bombarded at 500eV at 45 degrees from the normal. These modulations may be effective for liquid crystal alignment. more.
CCMR & Loctite: Interaction with Industry
Nugget :: Christopher Ober :: Jan 1, 2002
In a collaboration supported through the CCMR Polymer Outreach Program in partnership with Loctite, Cornell researchers have invented reworkable thermosets. These adhesives have been commercialized for use as removable underfills (Loctite 3567, http://www. loctite. com/new/3567release. html), the material that holds computer chips to substrates. more.
Programas Educativos
Nugget :: :: Jan 1, 2002
Professor Hctor Abrua, a member of the Cornell Center for Materials Research, explores the nature of chemical reactions using cornstarch and water with children in the Esperanza program in Ithaca, NY. Esperanza focuses on Latino students in grades Kindergarten through 6th grade; lessons are conducted in Spanish. more.
Educational Outreach
Nugget :: :: Jan 1, 2002
Ann Phinney-Foreman uses a glove box to prepare a sample of tert-butylpyridine tungsten chloride. Ms. Phinney-Foreman is a Chemistry teacher from Waverly High School in south-central New York State and worked with MRSEC Director Frank DiSalvo during the Research Experience for Teachers (RET) program in the summer of 2001 at Cornell. She has been accepted as a participant in the IBM-Almaden RET program for the summer of 2002. more.
OLED's Based on [Ru(bpy)3]+2 Pendant Dendrimers
Nugget :: H.D. Abruña, G. Malliaras, and P.L. Houston. :: May 1, 2001
We have developed organic light emitting diodes (OLED's) based on polyamidoamine (PAMAM) dendrimers generations 0-4 containing, respectively 4, 8, 16, 32 and 64 [Ru(bpy)3]+2 pendant chromophores on the periphery. (A shows the structure of dend-8-[Ru(bpy)3]). Thin films (70-100 nm) of these materials were spin-coated onto indium/tin oxide (ITO) glass and Ca electrodes (with a thin Al top layer) were vacuum deposited on top of the dendrimer film. (B shows a schematic of the cell employed). more.
Atomically Flat Si Mesas by Supersonic Beam Deposition
Nugget :: Doohan Lee, Todd Schroeder, Jim Engstrom, Jack Blakely. :: May 1, 2001
Atomically flat surfaces and interfaces are desirable for many electronic devices and multilayer structures. In this work the technique of deposition from a supersonic beam of Si2H6 has been combined with nanopatterning methods to create arrays of mesas on Si (111) which are free from atomic steps. Si is deposited on a surface patterned as in figure(1) at a rate of about one atomic bilayer per second at ~850C. more.
Mobility-Dependent Charge Injection at the Metal/Organic Interface
Nugget :: Yulong Shen, Matthias Klein, Daniel Jacobs and George Malliaras (PI). :: May 1, 2001
How can we make Ohmic contact to an organic semiconductor? Despite the tremendous technological advances in organic semiconductor devices over the past decade, we are still not able to answer this question. more.
Polyolefin-Silicate Nanocomposites: In Situ Catalyst Intercalation and Polymerization
Nugget :: J.S. Bergman, H. Chen, E.P. Giannelis, M.G. Thomas, G.W. Coates (PI) :: May 1, 2001
Polymer nanocomposites are an intriguing class of new materials composed of layered silicates intercalated by polymer chains. These hybrid materials typically exhibit dramatically improved properties compared with either their pure polymer components or inorganic constituent. Performance enhancement, such as increased modulus and barrier to gas and solvents, as well as decreased thermal expansion, depends on the spatial orientation and interactions of the polymer and silicate. more.
Colossal Magnetoresistance Thin Films and Nanostructures
Nugget :: Yan Wu, Yana Matsushita (00), Lisa Berndt and Yuri Suzuki (PI) in collaboration with Andrew Kent at New York University. :: Aug 1, 2000
Doped perovskite manganites are of interest because they exhibit colossal magnetoresistance and, perhaps more importantly, they may be half-metallic, with complete spin polarization at the Fermi level. Therefore this class of materials has been identified for potential magnetoresistive memory devices. Doped manganites also provide a model system for studying the influence of micromagnetics on the transport properties of magnetoresistive devices. more.
Kinetic Monte Carlo Simulation of Polycrystalline Copper (100)
Nugget :: Liguo Wang (graduate student), Markus Rauscher, Paulette Clancy (PI). :: Aug 1, 2000
A Kinetic Monte Carlo (KMC) simulation technique has been developed at Cornell in which a simple representation of grain boundaries can now be incorporated. Diffusion is not permitted across isotropically oriented grains and this allows us to observe a transition from columnar to dendritic (porous) growth as the angle of incidence of the beam shifts from normal to grazing angles. more.
High Spatial Resolution Electron Energy Loss Spectrometer (SREELS)
Nugget :: Nan Jiang and John Silcox (PI), J. Applied Physics 87, 3768 (2000). :: Aug 1, 2000
A scanning transmission electron microscope (STEM) equipped with a parallel electron energy-loss spectrometer (PEELS) has been improved to probe electronic states and associated chemistry on a near-atomic (~2 ) spatial scale. A detailed understanding of the excellent adhesion of Cr thin films to oxide glasses has been achieved by means of these studies. A thin Cr diffusion layer (~ 50 ) is now seen at the interface, originating with the inter-diffusion between Cr and alkaline earth ions (e. g. more.
Nanosurgery on MEMS
Nugget :: Led by Alan Zehnder, Harold Craighead, and Jeevak Parpia (PI). :: Aug 1, 2000
Micro- and nanoelectromechanical devices (MEMS and NEMS) with a high potential for use in radio frequency applications, sensors, etc, have been fabricated at Cornell by state-of-art electron-beam lithography tools. A combination of the scanning tunneling microscope (STM) and electron microscope (SEM) is used in a new technique for accurate control and analysis of the emerging nanomechanical structures. more.
New Mechanism For Controlling Magnetic Domains
Nugget :: E. B. Myers, D. C. Ralph, J. A. Katine, R. N. Louie, and R. A. Buhrman :: May 1, 2000
Magnetic devices for information storage currently operate by using externally- generated magnetic fields to control the orientation of the magnetic north and south poles. We have demonstrated a new mechanism for controlling magnetic domains, that instead relies on the quantum-mechanical interaction between the intrinsic spins of electrons and a magnetic material. more.
Engergetic Beam Enhanced Nucleation
Nugget :: Randy Headrick, Arthur Woll, Stefan Kycia, Joel Brock (Cornell), and Ramana M.V. Murty (ANL) :: May 1, 2000
Engergetic Beam Enhanced Nucleation Gallium Nitride and has become a very important material for a variety of applications, including blue and violet light-emitting diodes, lasers, and high-power transistors. The material is created in the form of a thin-film, one hundred times thinner than a sheet of paper, that is a nearly perfect single-crystal. more.
Ultra-Low Current Scanning Tunneling Microscope
Nugget :: Jack Blakely and Kit Umbach, CCMR IRG2 Thin Films on Glass :: May 1, 2000
Scanning Tunneling Microscope (STM) imaging with sub-picoamp currents allows structural and electronic characterization of materials normally considered insulating, such as oxides and glasses. The image of the native oxide of silicon shows that structural features of the crystalline substrate are observable on the rough oxide surface. The IV curve indicates a surface bandgap characteristic of silicon dioxide. more.
Liquid Crystalline Semiconductors
Nugget :: Led by Prof. George Malliaras (Seed), Materials Science & Engineering, Cornell and Prof. Twieg at Kent State University. :: May 1, 2000
Organic semiconductors are attracting a great deal of attention because of their ease in processing, which is superior to that of inorganic semiconductors. However, the penalty in terms of performance remains very high. Carrier mobilities in organic materials are several orders of magnitude lower than those in Si, imposing a severe limit on the performance of organic devices. Researchers at Cornell are developing a novel family of semiconductors, with exceptionally high transport properties. more.
Tunable Micromechanical Oscillator
Nugget :: M. Zalalutdinov (Postdoctoral Associate), B. Ilic and D. Czaplewski (Graduate Students), H. G. Craighead, J. Parpia, and A. Zehnder (PIs). :: Jan 1, 2000
The movement of tiny mechanical devices is important in a number of devices such as atomic force microscopes, magnetometers, frequency filters, optical switches for telecommunications, and biological sensors. Applications have been limited, however, by the fact that the oscillators could only oscillate at fixed resonant frequencies. This has changed now because of work done at Cornell, where a cantilever, tunable from 9. 6 kHz all the way up to 37 kHz, has been demonstrated. more.
Semiconductor Technology: Smoothing the Way
Nugget :: Y-C Huang, J. Flidr, T.A. Newton and M.A. Hines :: May 1, 1999
Researchers at Cornell University have used simple chemistry to produce atomically smooth silicon surfaces. To the naked eye, the silicon wafers used by the semiconductor industry have perfect, mirror finishes. But on an atomic scale, however, these mirror surfaces are actually rough and pitted. When microprocessors are manufactured from these wafers, this atomic scale roughness is then transferred to individual transistors, where it seriously degrades performance. more.
Metal Cluster Centered Star Polymers
Nugget :: Marc Weimer, Dhandapani Venkataraman, Frank DiSalvo and Dotse Sogah. :: May 1, 1999
A variety of organic molecules (ligands) can be attached to metal clusters such as W6Cl8+4 or Mo6S8. These clusters can then be dissolved in a variety of solvents. We have designed a special ligand that imparts solubility as well as containing an initiator for the polymerization of styrene. Since there are six metal centers per cluster, up to six polymer arms can be grown by attaching up to six of these ligands. The resulting polymer is a "star" polymer. more.
Local Dynamics of Polymers
Nugget :: D. B. Zax, D.-K. Yang, R. A. Santos, H. Hegemann, E. P. Giannelis, and E. Manias :: May 1, 1999
Fluids in confined between walls only nanometers apart exhibit remarkable dynamical heterogeneities on length scales as short as a few AA, though few experimental probes are available which test the origins of these heterogeneities on a microscopic scale. Our recent experiments combine nuclear magnetic resonance spectroscopy and molecular dynamics simulations to study the trilayer system formed when poly(styrene) (PS) is intercalated into a surface-modified fluorohectorite. more.
Exceptionally Ordered Hexagonal Arrays of Redox-Active Dendrimers via Metal-Initiated Self-Assembly
Nugget :: D. J. Díaz, G. D. Storrier, K. Takada, H. D. Abruña :: May 1, 1999
There is a great deal of interest in the preparation of surface structures of deliberate architecture with particular emphasis on systems capable of self-assembly. The binding of transition metals to specifically designed ligands provides an excellent platform for the preparation of such structures since both the strength and kinetics of binding can be exquisitely controlled. We have prepared terpyridine containing dendrimers (Fig. more.
Anisotropic Stress Effects in Sub-Micrometer Metal Films
Nugget :: :: May 1, 1999
Copper is replacing aluminum as the material of choice for the microscopic "metallization" wires that connect the various parts of integrated circuits together due to its lower resistivity. Unlike aluminum, however, copper is very anisotropic the elastic stiffness varies by more than a factor of two with grain orientation. Combined with the nanometer scale of these objects, this can lead to very unusual behavior which does not occur in bulk copper. more.
Snowflakes, Dendrites, and Welding
Nugget :: Professor Eberhard Bodenschatz, Department of Physics, Cornell University. :: Nov 1, 1998
Though the intricate structure of a snowflake is familiar to many, less well known is the occurrence of similar dendritic structures during the solidification process of many alloy systems. When metals are welded together it is frequently the case that the dendritic form of the solidification can determine the welds resulting mechanical properties. more.
Hard Drives and Spin Filters
Nugget :: V. Ambegaokar, P. Brouwer, R. Buhrman, H. Craighead, C. Henley, J. Parpia, D. Ralph, R. Richardson, Y. :: Nov 1, 1998
Shashi Upadyhay and Robert Buhrman in IRG4 of the Cornell Center for Materials Research have developed a new technique which, for the first time, allows measurements of the electron-spin-filtering properties of a single layer of magnetic metal. In these experiments the single layer is as thin as one atomic layer. more.
Bonding of metals to glass!
Nugget :: N. Ashcroft, D. Ast, S. Baker, J. Blakely, R. Dieckmann, J. Engstrom, H. Hui, C.-Y. Li, J. Silcox, K. Umbach. :: Nov 1, 1998
The adhesion of metal films to glass is technologically important, but not well understood at a fundamental level. To clarify it, Ashcroft and Neaton (in the Thin Films on Glass IRG of the Cornell Center for Materials Research) have calculated, ab initio, the adhesion of chromium to SiO(2) and found extensive rearrangement of the bonding at the interface. more.
Thin Film Transistors but on Glass Ceramics!
Nugget :: N. Ashcroft, D. Ast, S. Baker, J. Blakely, R. Dieckmann, J. Engstrom, H. Hui, C.-Y. Li, J. Silcox, K. Umbach. :: Nov 1, 1998
The low softening point of glass generally prevents use of the common semiconductor processing steps of diffusion and oxidation (which operate at high temperatures) to make transistors on glass substrates covered with a thin Si film. Researchers at the Cornell Center for Materials Research working with Corning Inc. more.
Patterns on Surfaces: Erosion, but with Order
Nugget :: M.V. Ramana Murty, T. Curcic, A. Judy, B.H. Cooper, A.R. Woll, J.D. Brock, S. Kycia, and R.L. Headrick :: Jul 1, 1998
Erosion of surfaces with energetic ions is an important step in many crystal growth and semiconductor processing techniques. Novel approaches are providing unprecedented control of surface structure at the atomic scale. Scientists at Cornell University have used synchrotron X-ray scattering to observe atomic layers disappearing in real time during the erosion of a single crystal metal surface with energetic ions. more.
