Undergraduate/Graduate Programs

2010 REU Projects

This list will be updated as projects are finalized.

• Directing Self Assembly on Semiconductor Surfaces
• Combinatorial Synthesis of Water Splitting Photocatalysts
• Synthesis and Electronic Transport Properties of Graphene: Single Graphite Layers
• Switching of Ferroelectric Domains in Multiferroic BiFeO₃ Thin Films
• Interaction Between a Nanoparticle and a Liquid Crystal: Applications in Photovoltaics
• Advanced Nanomaterials for Lithium Storage
• Smart Magnets for Next Generation Information Technology
• Optical Metamaterials
• Probing Plasmonic Near-Field Intensities with Fluorescence

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Directing Self Assembly on Semiconductor Surfaces

Research Advisor: Dr. Ray Phaneuf

A mean of fast assembly of extremely large numbers of nanostructures with positional and size control will be required if technology is to keep pace with the ever decreasing size scale of devices called for by such timetables as Moore’s Law and the international technology roadmap for semiconductors. Directed self-assembly, in which a template influences the otherwise spontaneous arrangement of atoms during processes such as growth is an appealing candidate for achieving this. Production of the template itself can involve self-organization or a combination of a lithographic step followed by self-organization. This project will involve experiments and modeling aimed at understanding how competing energetic, kinetic and geometric effects can be tuned to direct self-organization during molecular beam epitaxial growth of gallium arsenide. The student will learn how to characterize evolution of topography during growth using atomic force microscopy, and will interact with a research team carrying out both experiments and kinetic Monte Carlo-based simulations.

Combinatorial Synthesis of Water Splitting Photocatalysts

Research Advisor: Dr. Ichiro Takeuchi

For renewable energy generation, efficient production of hydrogen is crucial. Currently, there are a limited number of techniques by which water molecules can be split for generation of hydrogen. In this project, we will develop a simple, yet effective platform for combinatorial search of new water splitting photocatalysts. An ink-jet printer will be used for printing combinatorial libraries of candidate compounds. A Lego-block based rapid-screening stage will be developed. The student will be able to design and fabricate combinatorial libraries of water splitting photocatalysts. The library will be screened for photocatalysis using a diode laser. The project will allow the student to develop a complete combinatorial experiment and to directly work on a critical energy-related materials topic.

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.

Switching of Ferroelectric Domains in Multiferroic BiFeO₃ Thin Films

Research Advisor: Dr. Lourdes Salamanca-Riba

We are investigating the switching of ferroelectric domains under different strains. Ferroelectric domains in these materials form by the displacement of ions of opposite charge along opposite directions under an applied electric field. We are investigating the role of strain in BiFeO₃ films on their ferroelectric properties. We are also investigating the role of grain boundaries on the switching mechanism in these films. In addition, we are investigating if there is a gradient in the concentration of Fe³⁺/Fe²⁺ across grain boundaries and domain boundaries that could affect the switching behavior of these multiferroic materials. This project will involve the growth of films of BiFeO₃ using pulsed laser deposition, characterization of the ferroelectric properties of the films, characterization of the structure by X-ray diffraction and preparation of samples for TEM observation. 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 Fe³⁺/Fe²⁺ concentration gradient across domain boundaries and grain boundaries. These results will be related to the ferroelectric and ferromagnetic properties of the films in an attempt to understand the switching mechanism of ferroelectric domains under different amounts of strain.

Interaction Between a Nanoparticle and a Liquid Crystal: Applications in Photovoltaics

Research Advisor: Dr. Luz Martinez-Miranda

A nanoparticle which is comparable to the molecular size of the liquid crystal (~ 3- 5nm) will interact with it such that the liquid crystal will disorder or order depending on the preparation conditions of the nanoparticle and the concentration of the nanoparticle in the liquid crystal. We have shown that ZnO nanoparticles dispersed in a liquid crystal can: a. align the liquid crystal; b. increase the amount of current that flows through the nanoparticle/liquid crystal system; and c. produce the largest change in V_oc in the system. These quantities can improve further if we: 1. Use an aligning film for the liquid crystal; 2. use different size nanoparticles and nanowires; 3. different electrodes 4. Different liquid crystals; 5. Different nanoparticles such as TiO₂ or CdSe to see if the changes observed above are improved. We will concentrate on using an aligning film for the liquid crystal and use different size nanoparticles (1 and 2 above) and compare them to what has been already obtained in order to determine if we observe an improvement.

Advanced Nanomaterials for Lithium Storage

Research Advisor: Dr. John Cumings

Many emerging technologies, including electric vehicles, are looking for new higher density energy storage materials. One of the most promising areas in terms of ease of use, fast charge/discharge, and ultimate energy density is lithium storage for lithium ion batteries. Explorations in this area are now incorporating new advanced nanomaterials, such as silicon nanowires, with promising results. However, many of the underlying properties of the nanowires are not well understood and are limiting the life-cycle stability of these new materials. In this project, the student will work with scientist synthesizing high-performance lithium storage nanomaterials to help characterize their properties and how they might be utilized in a future generation of batteries.

Smart Magnets for Next Generation Information Technology

Research Advisor: Dr. John Cumings

Magnetic materials have high utility for information storage, and have enabled the fast growth of computing power over the past decades. However, all technologies that record to magnetic information media make use of high electric currents to store information. This dissipates energy as heat and results in inefficiencies in speed and scalability. In this project, the student will characterize the properties of new smart magnets that respond to stimuli other than magnetic fields or electric currents. Stimuli such as elastic deformation (strain) or electric fields could result in highly-improved information storage media.

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.

Probing Plasmonic Near-Field Intensities with Fluorescence

Research Advisor: Dr. Ray Phaneuf

Particle and surface plasmons are electromagnetic excited modes that can couple to light and are confined to the surface of metal films or the vicinity of metal nanoparticles. In particular, gold and silver sustain plasmonic modes at visible light energies. Because of plasmons’ high confinement, they exhibit high electric field intensities near the metal film or particle surface. Surface plasmons in particular may propagate along the metal surface, and their wavelength is less than that of free-space light. These properties make plasmons potentially useful in applications where excitations couple to light (e.g. photovoltaics and fluorescence) or optical devices more compact than light’s wavelength would normally allow. In this project, we are using a fluorescent layer of molecules 8 nm away from silver nanoparticles’ surfaces to determine the electric field intensity of these particles’ plasmonic modes. The Ag nanostructures are patterned with e-beam lithography, fabricated using standard clean room techniques, and characterized with a laser scanning microscope (LSM).