Undergraduate/Graduate Programs

2008 REU Projects

• Synthesis and Electronic Transport Properties of Graphene: Single Graphite Layers
• Synthesis of Nanotubes and their Applications
• Modeling and Numerics for Crystal Surfaces under Stress: How Math Works from Nano- to Larger Scales
• Project in Directed Self Organization at Moving Interfaces
• Biomicrofluidic Environments: a Laboratory to Understand Cellular Response
• Theory and Computer Simulations of Molecular Monolayers and Organic Donor-Acceptor Interfaces
• Optical Metamaterials

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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. However, extrinsic effects, such as interaction with the substrate and adsorbed molecules, play a large role in determining the properties of graphene. 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 controlled introduction of adsorbates to graphene in ultra-high vacuum to study impurity scattering, superconductivity, and the Kondo effect; imaging electron transport in graphene via scanned-probe techniques, and/or controlling the electronic device properties via interaction with tailored substrates.

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 nanotube structure can play also a very important role in the application of electronic devices. Conductive polymers are indispensable materials for the development of organic electronic devices, such as electrochemical power sources and flexible displays. One of very important issues in such electronic devices is poor charge transport rate due to slow diffusion of counter-ions in to the conducting polymer film during redox processes. Nanotube structure of conductive polymer is one of the ideal structures to enhance the device performance by improving charge transport rate as well as surface area because the counter-ions inside of the nanotube are ready to diffuse into the thin wall thickness of the nanotube without sacrificing electrical and optical properties. The fast redox process through the nanotube structure can be also applied to the development of supercapacitor. The fundamental study of super-capacitive properties will be discussed based on the PEDOT nanotube structures.

The REU student will learn how to synthesize these nanotubes using various materials such as SiO₂, conducting polymers, and other metal oxides 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.

Modeling and Numerics for Crystal Surfaces under Stress: How Math Works from Nano- to Larger Scales

Research Advisor: Dr. Dionisios Margetis

Crystal surfaces are used widely in the fabrication of small electronic devices. A crucial question is how mechanical and other properties of surfaces at large scales are affected by processes at smaller (even atomistic) scales.

My research focuses on the description of crystal surfaces by use of equations and computer simulations. My goal is to predict how the shapes of small structures (nanostructures) on surfaces change with time. Important factors that influence these changes are temperature and stress, which can be controlled in laboratory experiments. Stress is caused either by external mechanical forces or by the material itself, say in a thin film because of a `mismatch' between the structures of two crystals that are in contact. At large scales, the effect of stress can be described by differential equations, which are solved numerically. At smaller scales, there are more than one ways to describe the effect of stress.

One method is to use discrete equations. The REU student will learn different methods of describing crystal surfaces under various conditions including stress. He or she will address the latest problems in solving the related equations numerically by computer and analytically by pen and paper. This work will enable us to compare theory with available experimental data to help build future electronic devices.

Project in Directed Self Organization at Moving Interfaces

Research Advisor: Dr. Ray Phaneuf

This project involves investigation of instabilities and pattern formation at surfaces of semiconductor and low-k dielectric materials during growth, etching and annealing. The student will participate in characterization of templated surfaces before and after the above processes using atomic force microscopy (AFM), as well as numerical simulations of the morphology changes which occur.

Biomicrofluidic Environments: a Laboratory to Understand Cellular Response

Research Advisor: Dr. Gary Rubloff

Working with bioengineers and microsystems researchers, our group has pioneered the development of microfluidic systems to replicate the sequence of chemical reactions that occur in cells, aimed at understanding the biochemistry and discovering new antimicrobial drugs. We are now extending this to capture and maintain live cells in microfluidic environments so that we can investigate how cells respond to specific stimuli. The primary emphasis is on developing techniques to measure the cellular response in real time and to assess how cells respond to particular kinds of nanoparticles whose health and environmental effects are not yet understood. The REU student will work with graduate students to design and fabricate microfluidic networks, introduce cells into them, and use optical and chemical methods to monitor how the cells respond. The experience will provide a perspective on key issues in nano-bio technology at both biomolecular and cellular levels.

Theory and Computer Simulations of Molecular Monolayers and Organic Donor-Acceptor Interfaces

Research Advisor: Dr. Daniel S. Kosov

Molecular monolayers provide a unique link between the science of organic interfaces and technologies that seek to exploit their adaptable character. Molecular monolayers are model systems for the study of organic interfaces and are of technical interest for the fabrication of sensors, photovoltaic devices, transducers, protective layers, for lubrication, and as pattern formation materials. While qualitative structural models of monolayer films can be deduced from the scanning tunneling microscope images, theory is needed to decipher the intermolecular forces that control this varied architecture. We will use recent advances in the theory of molecular interactions to develop highly accurate intermolecular force fields from the ab initio wavefunctions of the molecules. These force fields will be used to provide a coarse-grained description of molecular monolayers that accurately capture morphology, domain boundaries for binary mixtures, and cohesive free energy.

The REU student will focus on predicting efficient organic photovoltaic device structures. It will require simultaneous optimization of interfacial electronic properties (band alignment, coupling across the interface, and dynamics of charge transfer) and nanoscale morphology (degree of phase separation, domain size).

Optical Metamaterials

Research Advisor: Dr. H. Dennis Drew

Using modern synthesis techniques it has recently become possible to engineer new artificial materials -metamaterials - based on nano-particles. These materials have novel properties that can find many uses in many fields, including optics and nano-optics. Examples are micro lenses, invisibility cloaks, and ultrahigh spatial resolution imaging systems. The REU student will design new metamaterials and applications of these materials. He/she will also learn to synthesize metamaterials and characterize them with optical measurements. He/she will also work on the theory of these materials based on software that performs finite element calculations of electromagnetic fields.