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Undergraduate Researcher: Elizabeth Avelar Mercado
Intended Major: Electrical Engineering
Home Institution: Merced College
Research Project: Deposition of Ohmic Contacts on NanoLEDs Devices by Surface Cleaning
Faculty Advisor: Prof. Ming C. Wu
Graduate Student Mentor: Seth Fortuna
UC Berkeley Department: Electrical Engineering & Computer Sciences Department
Project Abstract: NanoLEDs are seen as a possible light source components of optical interconnects in the replacement of electrical interconnects. However, many problems have to be solved for this to become a reality. NanoLEDs suffer from a high contact resistance (~10-4 ohm-cm2). This is detrimental to the device performance and reliability because of the excess heat generated from the large voltage drop due to the series resistance. Native oxide on InP surface is considered to be one of the factors that contribute to the high contact resistance since it works as an insulator, which makes it really hard for the device to conduct current. In this experiment, Transfer Length Method (TLM) test structures were fabricated. The native oxide on some of the structures was removed by the application of different compositions of HCL and H2SO4 while other structures were left untreated with the purpose of comparison of final results. Contact resistivity, Pc, was extracted from the samples afterwards. The results are analyzed, and the optimum cleaning method is discussed.   - Click HERE for the project poster.

Undergraduate Researcher: Thomas Chan
Intended Major: Materials Science and Chemical Engineering
Home Institution: Las Positas College
Research Project: The Effect of Annealing on the Insulator to Metal Transition in VO2 Nanowires
Faculty Advisor: Prof. Junqiao Wu
Graduate Student Mentor: Kevin Wang
UC Berkeley Department: Materials Science & Engineering Department
Project Abstract: Vanadium dioxide (VO2) is a unique semiconductor with an insulator-to-metal transition (IMT) that makes it useful for scientific applications, such as micro-actuator and infrared sensors. The transition temperature (TIM) can be modified by straining the nanowire, or by doping it. The key goal of this research is to study the effects of annealing cyclically across the IMT on W doped VO2 nanowires. Our experiments show a cycle-based anneal does not produce any enhancement in W diffusion compared to single step anneals.   - Click HERE for the project poster.

Undergraduate Researcher: Kevin Crabbe
Intended Major: Electrical Engineering and Computer Science
Home Institution: Diablo Valley College
Research Project: Developing a Multilayer Metallization Scheme for the Marvell Nanolab CMOS 2010 Baseline Run
Research Advisor & Mentor: Dr. Jeffrey Clarkson
UC Berkeley Organization: Marvell NanoFabrication Laboratory
Project Abstract: The Marvell Nanofabrication Laboratory CMOS Baseline process is in need of a multi-level metallization scheme in order to have a platform to build NEM relays, nanoelectromechanical devices that could potentially replace certain kinds of transistors. The scheme consists of two interconnecting metal layers and a dielectric material for isolation. When the metal layers cross over one another and isolation is desired, the dielectric material must be between them. This project makes use of a low temperature oxide (LTO) / spin on glass (SOG) / LTO thin film stack for isolation. The first LTO film, ~1000 Å, is deposited using low pressure chemical vapor deposition (LPCVD) and is very conformal to the existing topography on the wafer’s surface. The wafer is spin coated with SOG and fills trenches and flows over steps. The final deposited LTO film is ~2 µm thick and is planarized using chemical mechanical planarization (CMP). In order to characterize the planarity and quality of the two dielectric films, a scanning electron microscope (SEM) will be used to analyze the cross-section of the films covering trenches and steps. Additionally, optical measurements will be used to monitor film thickness of the films throughout the fabrication process.   - Click HERE for the project poster.

Undergraduate Researcher: Abigail Edwards
Intended Major: Engineering
Home Institution: City College of San Francisco
Research Project: Analyzing the Intersections Between the Endoplasmic Reticulum and Lipid Droplets
Faculty Advisor: Prof. James Olzmann
Graduate Student Mentor: Milton To
UC Berkeley Department: Department of Nutritional Sciences & Toxicology
Project Abstract: The membrane embedded protein UBXD8 has been connected to ERAD and Lipid Droplet synthesis/breakdown. Our research has shown that the thioredoxin-like domain (THL) of UBXD8 is necessary to the binding of UBAC2, an ER protein that restricts trafficking of UBXD8 to lipid droplets. We hypothesize that the THL domain of UBXD8 alone is sufficient for binding UBAC2. The THL domain of UBXD8 was cloned to test this hypothesis through affinity purification and western blotting. As a second verification, fluorescence microscopy will be used. By elucidating protein to protein interactions that regulate ERAD and Lipid Droplet metabolism, it could develop into important implications for our understanding of lipid droplet function in cell biology and disease.   - Click HERE for the project poster.

Undergraduate Researcher: Michelle Gantos
Intended Major: Chemical Engineering
Home Institution: College of Marin
Research Project: Engineering Membrane Transporters to Increase the Available Cytosolic Acetyl-CoA in S. Cerevisiae
Faculty Advisor: Prof. Danielle Tullman-Ereck
Mentor: Stephanie Lopez
UC Berkeley Department: Department of Chemical & Biomolecular Engineering
Project Abstract: TAcetyl CoA (AcCoA) is an important starting molecule for the biosynthesis of many biotechnologically relevant metabolites, such as isoprenoids used as flavors and fragrances, biodiesels, and anticancer drugs. In the yeast Saccharomyces cerevisiae, AcCoA metabolism occurs in at least four subcellular compartments, yet no innate pathway exists for direct transport between compartments. Our research aims to increase cytosolic AcCoA levels by using protein transporters AT-1 and the yeast homologue YBR220C to move the molecule from the mitochondrial compartment into the cytosol. We investigate the insertion of targeting sequences for the mitochondrial inner membrane under constitutive promoters of varying strength to properly localize these protein transporters.   - Click HERE for the project poster.

Undergraduate Researcher: Brenden Kallaby
Intended Major: Physics and Mathematics
Home Institution: Shasta College
Research Project: Graphene Nanoribbons - Molecular Fabrication on an Insulating Surface
Faculty Advisor: Prof. Michael Crommie
Mentor: Giang Nguyen
UC Berkeley Department: Department of Physics
Project Abstract: Graphene nanoribbons (GNRs) are quasi-one-dimensional strips of graphene with widths on the nanometer scale. Based on their size and geometry, they possess unique electro-magnetic properties and tunable band gaps which are nano-device relevant. To harness these characteristics of GNRs, it is essential to produce them with atomic precision.1 Recent successes with bottom-up fabrication show how precise GNRs can be synthesized on a metal surface. Our goal is to use bottom-up methods to grow GNRs on an insulating surface. Insulating surfaces will serve as a better interface for the analysis and application of GNRs. This experiment demonstrates an ab initio approach to producing GNRs on BN/Cu(111). It was conducted using a scanning tunneling microscope (STM) under ultra-high vacuum.   - Click HERE for the project poster.

Undergraduate Researcher: Yone Phar Lin
Intended Major: Biochemistry
Home Institution: Las Positas College
Research Project: Investigation of Esterases’ Activity on Fluorescein Diacetate (FDA)
Faculty Advisor: Prof. John Dueber
Mentor: Zachary Russ
UC Berkeley Department: Department of Bioengineering
Project Abstract: Peroxisomes are the organelles that are found in all eukaryotic cells. They are mostly related to lipid metabolism and oxidation of substances. In the eukaryotic cells, proteins can also be targeted towards the peroxisomes, known as the matrix protein import. The membrane of these peroxisomes is essential as they allow passage for certain important substances. In this project, we are going to find out the most active esterase with the most effective digestion on fluorescein diacetate that will then be inserted in the peroxisome to test its membrane permeability. Five candidates of esterases will be cloned, expressed using golden gate cloning method and purified from the E.coli. In vitro activity assay of FDA and five different esterases will determine the best candidate that can be used in our vivo assay in the peroxisome. In future work, we will be localizing the best esterase with the FDA to find out the permeability of the peroxisomal membrane. Being able to bioengineer the peroxisomal membrane will be advantageous in isolating proteins and other biochemical substances.
- Click HERE for the project poster.

Undergraduate Researcher: Rattanah Mahal
Intended Major: Biochemistry
Home Institution: Reedley College
Research Project: Isolation and Classification of Nitrogen Fixing and Phosphate Solubilizing Bacteria
Research Advisor: Dr. Romy Chakraborty
Postdoc Mentor: Dr. Marcus Schicklberger
Hosting Organization: Lawrence Berkeley National Laboratory
Project Abstract: The elements N and P are essential elements for the growth and survival of plants. Yet plants are limited in their ability to fix elemental N from the atmosphere, as well as hydrolyze organic and inorganic phosphorous from insoluble compounds. To compensate for this shortcoming, plants form a mutualistic relationship with bacteria to obtain usable nitrogen and phosphate. Although the majority of plants that form nitrogen-fixing root nodules are in the legume family, new species of N2-fixing bacteria have been discovered in association with non-nodulating crops. The goal of this research lies in the identification of beneficial bacteria capable of fixing nitrogen and solubilizing phosphate. In this study, High-Throughput Isolation (HTI) was used to identify N fixing and/or P solubilizing bacteria from tobacco (Nicotiana tabacum). Overall five different phylogenetic orders were identified: Enterobacteriales, Bacillales, Actinomycetales, Rhizobiales, and Sphingobacteriales. The strain Kosakonia Oryzae ola 51 from the order Enterobacteriales, in particular, was identified as a nitrogen fixers by amplifying the nifH gene; those results were then confirmed by the acetylene reduction assay. Ultimately, the goal of this research is to decrease fertilizer dependency by engineering plants to attract diazotrophic bacteria.   - Click HERE for the project poster.

Undergraduate Researcher: Jose Padilla
Intended Major: Mechanical Engineering
Home Institution: East Los Angeles College and Los Angeles City College
Research Project: Particle-Laden Hemodynamics for Strokes
Faculty Advisor: Prof. Shawn Shadden
Postdoc Mentor: Dr. Debanjan Mukherjee
UC Berkeley Department: Mechanical Engineering
Project Abstract: Every year in the United States an estimated 800,000 strokes occur and of those an approximated 87% are classified as ischemic. While strokes are of a major concern especially with an aging population, due to the complicated nature of blood, very little is known about its flow behavior, hemodynamics, and emboli trajectories once they are introduced to the circulatory system. By analyzing the circulatory domain of atrial to pre-capillary vessels, we are able to generalize the behavior of blood to being that of an incompressible, Newtonian Fluid and apply it to state of the art Computation Fluid Dynamic (CFD) simulations and techniques. In doing so we are able to produce profound and invaluable information regarding the factors present in the predilection of particles as they traverse the complicated vessel system from heart to brain, resulting in potentially catastrophic stroke and subsequent brain injury.   - Click HERE for the project poster.

Undergraduate Researcher: Leyla Shams
Intended Major: Electrical Engineering
Home Institution: College of Marin
Research Project: Enhancement of SiO2 by Argon Ion Implantation with Specific Tilt Angle, Dose and Energy
Faculty Advisor: Prof. Tsu-Jae King Liu
Mentor: Peng Zheng
UC Berkeley Department: Electrical Engineering & Computer Sciences Department
Project Abstract: Argon ion implantation with specific tilt angle, energy, and dose can be used to enhance the etch rate of SiO2. To clarify the impact of Argon ion implant energy, dose and tilt angle on enhancing the etch rate of SiO2, SRIM simulations were carried out. The results show that argon ion implant with energy of 10 KeV, tilt angle of 23, and dose of 1.2x1015 ion/cm2 achieves the maximum damage to 20nm SiO2 layer while causing minimum damage to Si substrate layer. The result also shows that higher tilt angle results in a broader damage concentration of SiO2.

Undergraduate Researcher: Christian Thompson-Kucera
Intended Major: Bioengineering
Home Institution: Berkeley City College
Research Project: Removal of Endogenous Esterase Expression in S.cerevisiae
Faculty Advisor: Prof. John Dueber
Mentor: Bernardo Cervantes
UC Berkeley Department: Department of Bioengineering
Project Abstract: Yeast, Saccharomyces cerevisiae, has a potential to be engineered as a reactor for proteins and chemicals. We are studying the role of esterases in its cells. To do this we attempted to create a yeast strain with no expression of its six esterases. We used the new genetic engineering technologies of Golden Gate and CRISPR/Cas9 to remove, or “knock-out”, esterase expression.   - Click HERE for the project poster.

Undergraduate Researcher: John Trinh
Intended Major: Electrical Engineering
Home Institution: Ventura College
Research Project: Efficient Modeling of Subwavelength Diffractive Elements
Faculty Advisor: Prof. Eli Yablonovitch
Mentor: Tianyao Xiao
UC Berkeley Department: Electrical Engineering & Computer Sciences Department
Project Abstract: Solar cell efficiency can be improved by using multiple independently connected solar junctions and an optical system that laterally splits different wavelengths of sunlight into the appropriate solar cells. Such a spectral splitter can be made by using a textured dielectric that diffracts light. The simplest way to model a diffractive element is by approximating the texture as a thin phase shift mask; however, at subwavelength feature sizes, this model neglects the effects at the edges of the pixels. In this work, we propose a new method of modeling these edge effects by dividing the mask into equal vertical layers, in which each layer can be efficiently simulated by scalar diffraction.   - Click HERE for the project poster.

Undergraduate Researcher: Harvey Vazquez
Intended Major: Mechanical Engineering
Home Institution: Los Angeles Southwest College and East Los Angeles College
Research Project: Purification of Boron Nitride Nanotubes
Faculty Advisor: Prof. Alex Zettl
Mentor: Aidin Fathalizadeh
UC Berkeley Department: Department of Physics
Project Abstract: With the discovery of carbon nanotubes, CNTs, and the many properties of these tubes; from a unique combination of stiffness, strength, and tenacity compared to other fiber materials that more often than not lack one or more of these properties and thermal and electrical conductivity, a lot of interest has been placed on carbon’s periodic neighbors, boron and nitrogen. Boron nitride has been under the academic and industry spotlight for being capable of producing the same kind of tubes, boron nitride nanotubes (BNNTS), that carbon can but with some differences in characteristics. Some of the differences include a higher weight to strength ratio, wide band gap semi conductivity, and more thermally and chemically stable. BNNTs are also much more difficult to synthesize and until recently, could not be produced on a large scale. Purification is a critical post-production step following any synthesis and is the focus of the efforts presented here.   - Click HERE for the project poster.

Undergraduate Researcher: Husna Yasini
Intended Major: Biochemistry
Home Institution: Chabot College
Research Project: Isolation and Characterization of Oak Ridge (FRC) Ground Water
Research Advisor: Dr. Romy Chakraborty
Mentor: Angelica Pattenato
Hosting Organization: Lawrence Berkeley National Laboratory
Project Abstract: In the 1940’s Oak Ridge, Tennessee, transformed from farmland to atomic testing ground. Currently, field research takes place at a series of contaminated and uncontaminated sites at the US Department of Energy’s Oak Ridge Field Research Center. This study investigates microbes from groundwater that contains high plumes of uranium, technetium, nitrate, volatile compounds and has a pH ranging from 3-10. By isolating bacteria and using High-Throughput Isolation (HTI) techniques clonal isolates can efficiently and rapidly be characterized. Furthermore, select strains will be characterized to better understand how the groundwater microbes adapt to such contrasting geochemical gradients. A range of carbons are tested to see whether they can oxidize to CO2 or ferment. Several groundwater samples including FW602, FW215, FW012, FW106, and DP16D were isolated and identified with the 16rRNA found to be composed of several species of Pseudomonas and Bascillus. Research is ongoing, and multiple isolation techniques are used in hopes of obtaining a diverse collection of isolates as a result. Groundwater samples were tested for the ability to oxidize Humic. We are looking to find microbes than can use Humic substances as an electron donor for the anaerobic oxidation of organic compounds, by doing an iron assay. The finding that microorganisms can oxidize Humics has important implications for the mechanisms by which the microorganism oxidize organics in contaminated groundwater, and suggests that microbes have adapted to organics-contaminated groundwater.   - Click HERE for the project poster.