Summer 2012 REU Participants
Research Experience for Undergraduates (REU) for non-Tech Students:
The Research Experience for Undergraduates program provides a ten-week paid summer research experience for six students enrolled in undergraduate science and engineering programs at U.S. institutions. Students work on exciting ongoing Center research projects with the MRSEC faculty mentors and graduate students. They are housed on campus, and in addition to a $600 travel allowance, are provided with a meal plan and a $5,000 stipend. Seminars, GRE preparation courses, professional development and graduate school application workshops are organized to maximize the learning experience outside of laboratories. The REU students are being admitted through the Summer Undergraduate Research in Engineering/Science (SURE) program. More information and an online application is available at, www.sure.gatech.edu.
|GT MRSEC REU 2012 PROJECTS|
Participant Name & Affiliation
|Krista Burton, Xavier University||Electronic and Optical Properties of CVD Grown Graphene|
The rapid advancements of the past few decades have transformed America into a technologically dependent society with all people owning and relying on their own personal electronic devices. Since consumer demand for electronics are at an all time high, companies invest multiple millions of dollars in research and development to attack the problem of producing smaller, more efficient devices at reasonable prices. Graphene is a one atom thick layer of graphite with a two-dimensional honeycomb lattice. It has sparked the interests of many researchers for its unique electronic properties such as room temperature ballistic conduction and high electron mobility. A rise in the interest of graphene for applications such as transistors and touch screen electronics has occurred due to the material’s abundance, high transmission ability, and low resistive qualities. My lab has spent a great amount of time studying the more unexplored magneto-optical properties of CVD grown graphene films in vacuum environments. My work this summer will go towards testing the transmittance and resistance for their future measurements and characterization of graphene properties. I used an in-lab furnace to grow multiple samples of graphene for an ongoing optical project, and further processed and analyzed two samples using the following cleanroom devices: the Karl Suss RC8 Spin Coater, the Karl Suss MA-6 Mask Aligner, and the Plasma Therm RIE.
|Kodzo Deku, Georgia Tech||Functionalize Graphene for Electronic Applications||Graphene is a single layer of carbon atoms in a honeycomb structure with particular electrical and optical properties such as high carriers’ mobility, high current density, and high transparency. Due to these properties, doping graphene for organic electronic applications is receiving considerable attention. We demonstrated that graphene p-n junction can be formed using polyethylenimine, 80% ethoxylated (PEIE). This is a facile graphene junction that is thermally/environmentally stable. We also showed that the work function (W.F) of CVD graphene can be lowered by 1 eV after PEIE treatment. Functionalize graphene with PEIE is a facile, stable, and defect free method of doping graphene for electronic applications such as solar cells, transistors, diodes, and OLED.||Sam Graham|
|Giovanni DeLuca, University of West Florida||Instrument Design and Integration for the Photoresponse Studies of Excimer Laser Reduced Graphite||The purpose of this research is to determine the voltage and current alterations generated by laser reduced graphite oxide upon its exposure to light relative to a certain position on the sample. This particular characterization has not been done before on laser reduced graphite oxide, but is often used as a failure analysis technique for integrated circuits. To achieve the goal, an instrument was designed that controlled precisely when and where the sample was exposed to the light source. Integration of the sensing instruments (current/voltage source, nanovoltmeter, and picoammeter) and control of the XY-stage and the laser shutter was written with LabVIEW 8.6. The data will be compared to graphene and other photosensitive materials.||Thomas Orlando|
|Carlos Medina Garcia, UPR Mayaguez||Tuning the Wettability of HOPG Surfaces via Plasma Treatments||Wetting characteristics of HOPG have been studied and compared by applying different plasma treatments. An HOPG clean and contaminant-free surface was obtained after peeling it with Scotch tape for every of the experiments. The plasma treatments were performed at different powers, time exposures, and gas flow rates. Depending on the plasma treatment applied to the HOPG, the contact angle, CA, changed drastically, increasing in some cases and decreasing in others. The gasses used in the plasma treatment were argon (Ar), oxygen (O2) and sulfur hexafluoride (SF6). After applying different plasma treatments, the CAs were measured using a contact angle goniometer for each of the samples, obtaining specific characteristics from each different treatment. For the fluorine treatment in the HOPG surface was obtain a hydrophobic properties. While in the treatment of Ar plasma and Ar & O2 plasma hydrophilic properties were obtained. These differences in properties can be due to the chemical bonding and roughness of the HOPG surface. X-Ray photoelectron spectroscopy (XPS) and Atomic Force Microscopy (AFM) was conducted to obtain a better understanding of what was happening in the sample. The XPS showed that the plasma treatment for the SF6 contained approximately 9% fluorine. For the Ar plasma and Ar & O2 plasma treatments, the percentages of O2 were about 6% in both cases, but the contact angles for these samples differed by 10⁰. When applied with the SF6 plasma treatment, the HOPG demonstrated the most hydrophobic properties, whereas the Ar treatment caused it to display the most hydrophobic properties. Existing studies on the surface of HOPG will be further analyzed in order to explain the behavior of the observed hydrophobic properties. In order to obtain more information about the surface behaviors of HOPG in presence of different environments, an AFM analysis was performed for the same samples. The AFM technique can be very useful to study the surface roughness of a material; however, due to the minimum surface area of each sample, no realiable results were obtained. Considering this problem, we proceed to analyze the HOPG samples with Optical Microscope obtaining better images of the surface.||Dennis Hess|
|Angel Santiago Lopez, UPR Mayaguez||Rapid Fabrication of Microgel-Polyethylenime Films for Supported Enzyme Incorporation||Within the polymer science field, hydrogels emerge as potential platforms for diverse applications in biotechnology and biomedical research. Micro-sized hydrogels (Microgels) may fill up the latent need of biocompatible supporting agents for the immobilization of relevant macromolecules (e.g. proteins). This class of soft materials has proved to be capable of providing physical support in diverse scenarios. By the use of an active deposition technique, this research objective is the fabrication of anionic poly(N-isopropylacrylamide)-co-acrylic acid (NIPAm-co-AAc) microgels and linear polycation polyethylenimine (PEI) based films as an alternative for fully supported enzyme incorporation. The ease of functional film fabrication techniques was studied by comparing a layer-by-layer (LbL) build up approach versus the use of Microgel-PEI as a polyeletrolyte complex (PEC) for a one step film construction. Multilayer and complex formation was confirmed by Atomic Force Microscopy (AFM) and UV-Vis spectroscopy for LbL and PEC films, respectively. It was found that the optical density (OP) of LbL films linearly increased during the multilayer formation while PEC films showed OP dependence on Microgel-PEI mixing ratio. The widely studied model enzyme, peroxidase from horseradish (HRP), was then incorporated into the film network by passive adsorption and assayed for enzymatic presence. HRP loading into the films was analyzed as a function of the number of layers and mixing ratio, by using LbL and PEC respectively in order to determine the most reliable way to produce a biofunctional film that supports increased incorporation of a macromolecule.||Andrew Lyon|