The University of Maryland MRSEC grants ended in September 2013 after 17 years of successful operation. This site remains as a history of the center, but will not be actively maintained.

Undergraduate/Graduate Programs

2007 REU Projects

Synthesis and Electronic Transport Properties of Graphene: Single Graphite Layers

Research Advisor: Dr. Michael Fuhrer

It has recently become possible to synthesize graphene, a single atomic plane of graphite, in the laboratory. Graphene may have many of the advantages of carbon nanotubes for electronic applications: high charge-carrier mobility, high thermal conductivity, small electronic mass, etc. Graphene may additionally have the significant advantage over nanotubes that, while carbon nanotube growth results in a random distribution of nanotube diameters and chiralities, a graphene layer could potentially be processed into strips of identical width and direction relative to the graphene lattice (thus having identical device properties). The REU student will learn to synthesize single graphene sheets and fabricate devices from graphene using advanced lithography techniques. The student will address the latest problems in graphene electronics including patterning graphene device via etching, local patterning of graphene using scanning probe microscope-based lithography, imaging electron transport in graphene via scanned-probe techniques, and/or controlling the electronic device properties via local electrostatic gates.

Synthesis of Nanotubes and their Applications

Research Advisor: Dr. Sangbok Lee

Nanotube structures have a number of attributes that make them potential candidates for biomedical applications. First, nanotubes have inner voids that can be filled with species ranging from large proteins to small molecules. In addition, nanotubes have distinct inner and outer surfaces that can be differentially functionalized. The ability to control the dimensions allows for tailoring tube size to fit the biomedical problem at hand. Finally, the ability to make these nanotubes out of nearly any material creates the possibility of making nanotubes with a desired property such as ruggedness or biodegradability.

The REU student will learn how to synthesize these nanotubes using various materials such as SiO2, conducting polymers, and Fe3O4 by using alumina porous template film. The student will also approach problems in various applications such as targeted drug delivery, biosensors, membrane transports, and electronic devices.

Self-Assembly of Surfactant-based Drug Encapsulation Vessels

Research Advisor: Dr. Doug English

One area of particular interest in the English Group is self assembly. Self assembly refers to processes in which groups of molecules weakly associate to form larger, stable aggregates with very specific structure. These self assembly processes are important in how laundry detergents work, how walls form in living cells, and the way in which molecules coat certain surfaces. In our group, a REU student will study mixtures of cationic and anionic molecules that spontaneously form spherical shells (spontaneous equilibrium vesicles). These equilibrium vesicles can be used to encapsulate small molecules in solution. Molecules can remain encapsulated for weeks or months and their release can be intentionally triggered. These vesicles are promising storage and delivery vehicles for drugs, cosmetics and agrochemicals. As a REU student you will participate in studies aimed at deepening our understanding of how equilibrium vesicle properties change with composition. These results will be important in optimizing the performance of these molecular materials.

Ferroelectric and ferromagnetic films for magnetoelectric applications

Research Advisor: Dr. Lourdes Salamanca-Riba

We are investigating the formation of nanocomposites of ferroelectric and ferromagnetic oxide films grown under different oxygen partial pressure and temperatures. The films are grown by pulsed laser deposition on various substrates. For BiFeO3 films, for example, we have observed that the oxygen partial pressure plays a very important role on the formation of Fe2O3 columnar domains that are embedded in a matrix of BiFeO3. The films show larger magnetization than expected for BiFeO3 because of a formation of g-Fe2O3 within a-Fe2O3. Films with different extents of relaxation of the lattice mismatch also show different values of the magnetization. It is possible that there is variation in the concentration of the Fe:Bi:O within each phase in these materials which could be in part responsible for the enhancement in magnetization. In this project we will grow a series of films with different oxygen partial pressure and temperature and obtain detailed information of the structure and composition gradient across the different phases. These results will be related to the ferroelectric and ferromagnetic properties of the films in an attempt to understand the role of strain and composition gradient on the properties of these materials.

Zero Dimensional Nanostructures: Synthesis and Characterization

Research Advisor: Dr. Min Ouyang

This REU project will focus on rational chemical synthesis of both metallic and semiconductor quantum dots, aimed at controlling their size and shapes. Recently these nanomaterials have attracted significant interests from view points of both fundamental science and technological applications because their physical and chemical properties show dramatic difference from their higher dimensional counterparts (such as bulk) and can be engineered by tuning their size and shape due to the quantum confinement effect. The REU student working with this project will gain invaluable experience in chemical nanomaterial synthesis, nanomaterial structural and composition characterization by a variety of techniques (e.g., transmission electron microscope).

Combinatorial investigation of nanocomposite materials

Research Advisor: Dr. Ichiro Takeuchi & Dr. Makoto Murakami

Nanocomposite materials allow us to explore new functional materials. By combining materials with different properties at nanometer level, we can tune multifunctional properties of materials. We are interested in synthesizing superconducting/ferromagnetic nanocomposite materials using pulsed laser deposition. We will synthesize such materials using the combinatorial technique. The combinatorial approach provides a means to quickly investigate a large number of previously unexplored combinations of materials. High-throughput synthesis and characterization techniques are implemented to carry out highly integrated search-and-discovery processes. The result is that we can rapidly identify new nanocomposite materials with enhanced physical properties. The REU student will learn how to synthesize, design and characterize nanocomposite materials.

Hybrid molecule-metal nanoparticle arrays efficient light emission and absorption

Research Advisor: Dr. Ray Phaneuf

Noble metal nanoparticles (Au and Ag) interact very strongly with light due to the creation of charge oscillations called plasmons, an effect which has useful applications both in high efficiency sensing, and possibly in light energy harvesting. In this project, the student will participate in the fabrication and characterization of hybrid organic molecule-metal nanoparticle arrays to determine the size, shape and spacing of particles for highly efficient light emission and absorption.

STM measurements of isolated organic molecular monolayers

Research Advisor: Dr. William Cullen

There is currently much interest in the area of organic/molecular electronics. The primary advantages of organic semiconducting materials, as opposed to traditional inorganic materials such as silicon, are their flexibility, large-area coverage, and low cost. Much progress has been made in proof-of-principle and fabrication of organic field effect transistor (FET) devices. The key ingredient of an FET device structure is a semiconducting layer, electrically insulated from the gate electrode which controls its conductance by an electric field. In spite of this recent progress, there is much to be learned with respect to electronic transport in ultra-thin organic layers, the influence of substrate topography and electronic properties, and the coupling of the molecular layer to the contacts.

Recent experiments have shown that Pentacene molecules can be deposited on single-crystal metal surfaces following an initial growth of 1-2 monolayers of sodium chloride. The thin NaCl insulating layer allows effective decoupling of the molecular orbitals from the electronic states in the underlying metal surface, yet is thin enough that tunneling measurements are possible. This fortunate circumstance allows detailed STM measurements to be made on the molecular layer, while keeping it in an environment that more closely resembles an FET device structure. Such experiments are timely and relevant to the developing field of molecular electronics.

The REU student participating in this project would acquire relevant research experience in molecular transport, scanning tunneling microscopy, analysis of STM images, epitaxial layer growth, and ultra-high vacuum technology.

Liquid crystal - nanometer particle - surface termination interactions

Research Advisor: Dr. Luz Martinez-Miranda

This group studies the interaction of the smectic A liquid crystal - nanometer size particle of FeCo and surface termination of the particle system. The smectic-A phase of the liquid crystals is the phase of the walls of the cells in all living creatures, so this system is a model for biosystems. The liquid crystal nanometer particle surface termination system has also been studied for its potential display applications. The surface termination is necessary to ensure that the liquid crystal and the nanometer will not phase separate and to identify targets in biological applications. It also affects the way that the liquid crystal responds to the nanoparticle. We are studying this effect.

We have developed a phenomenological model to explain some of the behavior observed in the liquid crystal. Particles that are comparable in size to the liquid crystal (3nm) will have a disordering effect on the liquid crystal which depends on the surface termination. Part of our study looks into nanoparticles of sizes ranging from 2 nm to 8 nm in size to observe this disordering effect as a function of the surface termination. In this project we will have the student look at one or two nanoparticles in this range, with three or four terminations and analyze how the nanoparticle disorder the liquid crystal. The student will work with X-rays or with a microscope or both in determining such a disorder. To do this, we will analyze the resulting scan by using a Gaussian function and analyzing the peak position, the intensity and the width of the peak, which will give us information on the amount of liquid crystal that is aligned and the degree of disorder it has. The scans below, taken with a 2nm nanoparticle covered with NHS (N-hydroxy succinimide), show the effects of the disordering after the application of a magnetic field.

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