2012 Participants and Projects
Undergraduate Researcher: Franiece Bennett
Major: Electronics Engineering
Home Institution: Norfolk State University
Research Project: Dynamic Graphical Representation of Vertical Cavity Surface Emitting Lasers
Faculty Host: Connie Chang-Hasnain
Graduate Student Mentor: Wai-Son (Wilson) Ko
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: The incorporation of photonics with silicon CMOS can potentially lessen energy
consumption of data communication in microprocessors. The effectiveness of interfacing both electronic
and optical components in a device requires testing, graphical representation with the use of Matlab,
analysis, and interpretation of the measured results. The testing therein monitors the change in voltage
distributed onto a device for a given pump current and the plotting of the IV curve in comparison to the
correct characterization curve of the electronic component. The optical setup incorporates the monitoring, graphing,
and interpretation of the light emitted from the laser components.
- Click HERE to see the project poster.
Undergraduate Researcher: John Bryant
Major: Electrical Engineering
Home Institution: Florida International University
Research Project: Transport Measurements of Composite Multiferroic Heterostructures for Low-power Magnetic Anisotropy Control
Faculty Host: Jeffrey Bokor
Postdoc Mentor: Mark Nowakowski
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: The field of nanomagnetics has the potential to open new pathways for energy-efficient data processing and storage.
Nanomagnets rely on dipolar coupling to transfer data across a circuit with potentially 106 times more efficiency than traditional electrical
buses1. One of the challenges of this technology is to reduce the energy needed to clock a series of nanomagnetics. Much of the power saved
via nanomagnetic data transfer is lost by the power required to apply an external magnetic field. One solution is to create nanomagnetic
composite multiferroic heterostructures composed of piezoelectric and magnetostrictive materials to manipulate local on-chip magnetic fields
by modulating strain to control the magnetoelastic energy at the interface. We model the electrical field required to induce a magnetic easy
axis reorientation and measure the anomalous Hall effect transport properties of terfenol-D/piezoelectric heterostructure devices to
characterize the magnetoelastic interface. - Click HERE to see the project poster.
Undergraduate Researcher: Anna Colleen Crouch
Major: Polymer and Fiber Engineering
Home Institution: Georgia Institute of Technology
Research Project: Magnetotransport across Conducting Domain Walls in Bismuth Ferrite
Faculty Host: Ramamoorthy Ramesh
Postdoc Mentor: Guneeta Singh Bhalla
UC Berkeley Department: Materials Science and Engineering
Project Abstract: Over the past few decades, complex perovskites oxides have been extensively studied due to the wide range
of functional electronic phases they exhibit including highly correlated electron behavior, superconductivity, ferroelectricity
and magnetism. Multiferroics are a group of oxide perovskites which possess both a ferroelectric polarization and a magnetic order
which are coupled. Bismuth ferrite is a prototypical multiferroic with an additional unique characteristic. While the bulk material
is insulating, the ferroelectric domain walls separating two regions of differently oriented electric dipoles conduct electricity.
In this work, we probe the conducting domain walls via magnetotransport measurements in order to better understand their electronic
and magnetic properties. Due to the domain wall’s size and control achieved thus far in spatial control, we explore their potential
for electronic device applications. - Click HERE to see the project poster.
Undergraduate Researcher: Chen Dan Dong
Major: Applied Math and Electrical Engineering
Home Institution: Massachusetts Institute of Technology
Research Project: Study of Fully Depleted SOI MOSFET Performance for Power-Efficient Analog Circuit Applications
Faculty Host: Tsu-Jae King Liu
Postdoc Mentor: Nuo Xu
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: The impact of back biasing on tuning analog circuit performances for Fully Depleted SOI (FD-SOI) MOSFET
is studied. Several analog performance metrics, including transconductance (Gm), Gm/Id ratio, linearity and low-frequency noise
are evaluated for nanometer-gate-length devices, which provide insights for power-efficient circuit design based-on FD-SOI
technology platform. - Click HERE to see the project poster.
Undergraduate Researcher: Steven Drapcho
Major: Physics
Home Institution: Massachusetts Institute of Technology
Research Project: Strain Tuning of Structural and Electronic Properties of (Ba0.8Sr0.2)TiO3
Faculty Host: Sayeef Salahuddin
Graduate Student Mentor: Asif Khan
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: The study presents evidence of control over the structural and electrical properties of ferroelectric
thin films of epitaxial (Ba0.8Sr0.2)TiO3 (BSTO) through strain tuning. We use pulsed-laser deposition (PLD) to grow thin films
of SrRuO3-buffered BSTO on four different substrates: DyScO3 (DSO), GdScO3 (GSO), SrTiO3 (STO),
and NdScO3 (NSO). Using x-ray diffraction techniques, we find that the BSTO out-of-plane c lattice
parameter decreases with increasing tensile strain as expected.
We discover that the dielectric constant of BSTO decreases with c/a and therefore increases with tensile strain due to increased
dielectric polarizability. Frequency and Rayleigh analysis of the dielectric constant show high crystal quality free from defects,
indicating that the effect of strain on the dielectric constant is due to intrinsic rather than extrinsic
effects. - Click HERE
to see the project poster.
Undergraduate Researcher: Dale Karas
Major: Optical Engineering
Home Institution: University of Arizona
Research Project: Fabrication & Testing of Si-Photonic Waveguides for Loss Measurements of a Mach-Zehnder Interferometer in a MEMS Electro-Photonic
Heterogeneous Integration Platform
Faculty Host: Ming C. Wu
Postdoc Mentor: Niels Quack
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: The development of a frequency-modulated continuous-wave laser detection and ranging (FMCW-LADAR) source for a MEMS Electro-Photonic
Heterogeneous Integration (M-EPHI) platform, as primarily used for 3D-imaging applications, requires fabrication and testing to determine device efficacy.
As the heterogeneous integration of optical sources, silicon waveguides, and control electronics can enable low-cost, miniaturized range finders and high-bandwidth
communication systems, methods of testing and quantifying the effects of losses present within optical switching are necessary to gauge optimal efficiency of such a
proposed heterogeneous configuration. Testing for sources of loss of the waveguides enable the characterization of a passive Mach-Zehnder interferometer (MZI)
within the Si-Photonics layer, where modulation of output intensity can characterize weighted multicasting and equalization.
- Click HERE to see the project poster.
Undergraduate Researcher: Robert Orleans-Pobee
Major: Electrical Engineering and Physics
Home Institution: Virginia Tech
Research Project: Investigating Band-Edge Sharpness in GaSb/InAs Heterojunctions for Use in TFETs
Faculty Host: Eli Yablonovitch
Graduate Student Mentor: Jared Carter
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: While miniaturization has continued to develop according to Moore’s law, yielding
increased electronics performance, the overall pace of improvement is beginning to slow because power
requirements have remained largely the same. The leading source of power consumption in modern circuits is the
Metal-Oxide Field-Effect Transistor (MOSFET); therefore, in order to reduce power consumption and continue the
trend of increased performance, a mechanism needs to be found to operate these transistors at lower voltages.
One proposed low-voltage alternative to the MOSFET is the Tunneling Field-Effect Transistor (TFET),
which operates by manipulating the quantum tunneling effect in a P-N junction. For tunneling in a junction,
the conduction band on one side must line up with the valence band on the other, a condition that is met
in GaSb/InAs heterojunctions. However, in order for these heterojunctions to be viable in transistors,
the band edges must be extremely sharp. We intend to investigate the sharpness of these band edges,
using a variety of techniques, most notably developing a circuit for use in band-edge spectroscopy.
- Click HERE to see the project poster.
Undergraduate Researcher: Benjamin Osoba
Major: Electronics Engineering
Home Institution: Norfolk State University
Research Project: Simulation of 2D InAs/GaSb Heterojunction TFET
Faculty Host: Chenming Hu
Postdoc Mentor: Yuping Zeng
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: In this project, the possibilities for 2D simulation using the Nextnano3 simulation
program were explored. Specifically, a previously operational 1D simulation script was altered and
developed into that of a 2D simulation. The 2D script provides a template for the group to use, allowing
the 2D simulation to become more accessible and understandable. In this instance, the program was used
to analyze the characteristics of a 2D heterojunction InAs/GaSb TFET. The 2D simulation proved operational,
without errors in script which would result in incomplete compilation. There are still some components of the
program which need further analysis, such as the color-coded outputs which do not yet display a color-key.
- Click HERE to see the project poster.
Undergraduate Researcher: Peida Zhao
Major: Electrical Engineering
Home Institution: UC San Diego
Research Project: Investigating Material Properties of Tantalum Selenide and Tantalum Sulfide and Their Compatibilities in
Low Energy Devices
Faculty Host: Ali Javey
Graduate Student Mentor: Hui Fang
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: We fabricated back-gate and top-gate FET devices using two different transition metal dichalcogenides (TMDC)
systems, specifically TaS2 and TaSe2, as the channel material of a FET-like device. Previous studies of the TMDC family have indicated
semiconducting behavior of TaSe2 and TaS2 (with a bandgap of 0.25eV and 0.1eV respectively) at low temperature owning to the formation
of a gap in the Fermi surface, associated with the charge density wave effect (CDW). Our studies however, have shown metallic behavior of
both systems in bulk dimension (at ~6-7nm) at room temperature and low temperature with no gate dependence. Further investigations of the
material as we thin down layer thickness (<5 nm thick or <7 monolayers) have shown a “metal to insulator” transition where the materials cease to conduct.
Our investigation of the fundamental TaS2 and TaSe2 characteristics will hopefully pave the way for a newer generation of monolayer FETs using TDMC materials other
than MoS2 and WSe2.
- Click HERE to see the project poster.
2011 Participants and Projects
Undergraduate Researcher: Ayana M. Andalcio
Major: Electrical Engineering
Home Institution: Rice University
Research Project: Scheme for Observing Magnetization Dynamics of Nanomagnets with On-Chip Clocking
Faculty Host: Jeffrey Bokor
Postdoc Mentor: Mohammad T. Alam
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: A nanowire consisted of a line of antiferromagnetically coupled nanomagnets can produce unexpected
metastable states along the wire that affect the value of the output. This error has occurred both experimentally and through simulations.
Current optical microscopy can provide an image at one point in time of the nanowire, but cannot show the time evolutions of
the switching nanomagnets. A Photoelectron Emission Microscope uses probe x-ray radiation to emit electrons from a sample,
allowing a method to establish the magnetic state on the nanomagnets through the electron spin. Nanomagnets propagate data
through on-chip clocking by sending a current pulse along a copper wire to produce a magnetic field strong enough to cause the
nanomagnets to reach zero magnetization at its peak, and then stabilize to one of the two remnant states after the removal of the magnetic field.
Testing different blocks of the experiment design demonstrates that its implementation should work given that the right amplifiers, focusing optics,
and circuitry components are found. - Click HERE to see the project poster.
Undergraduate Researcher: Wei Dai
Major: Electrical Engineering
Home Institution: University of California, Riverside
Research Project: LAO-STO Tunnel Junction Structure Modeling
Faculty Host: Ramamoorthy Ramesh
Postdoc Mentor: Jan Seidel
UC Berkeley Department: Material Science and Engineering
Project Abstract: The interface of LaAlO3 and SrTiO3 semiconductors contain property of superconductivity and mobile electron gas.
LaAlO3 and SrTiO3 hetero-junction structures were constructed by epitaxially deposition. I-V Measurements were taken across the interface
to better understand the structure’s characteristics. The measurements had shown behavior of negative differential resistance at low bias voltage.
We investigate this behavior with theoretical quantum tunneling models produce by Mathematica software. We use the program to plot transmission
curves of the barriers of our choice. Comparison is made between the theoretical and lab model to identify the possible cause of negative differential resistance.
- Click HERE to see the project poster.
Undergraduate Researcher: Taron Hakobyan
Major: Chemistry
Home Institution: Los Angeles Trade-Technical College
Research Project: Investigation of Peptoids and Liposomes for Printed Biosensors
Faculty Host: Ana Claudia Arias
Graduate Student Mentor: Brian Lunt
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: This project investigated different materials in an attempt to produce biosensor switches
using thermosensitive liposomes and peptoids. The characteristics of electronic materials to be encapsulated in
liposomes are being examined. The researchers studied different methods of release suitable for inkjet printing conditions.
Peptoids were examined with the intention of forming monolayer nanosheets that may be spun, rolled, or printed on
substrates to create sensor switches. Fluorescence microscope, SEM, and AFM imaging are vital instruments
that were used to congregate the new knowledge. - Click HERE to see the project poster.
Undergraduate Researcher: Duanni Huang
Major: Electrical Engineering
Home Institution: MIT
Research Project: Investigation of Optical Antenna Coupled Nano-Photodiodes
Faculty Host: Ming C. Wu
Graduate Student Mentors: Michael Eggleston, Ryan Going and Amit Lakhani
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: Nanometer-scale photodiodes coupled with optical antennas are promising candidates for optical interconnect receivers.
Two antenna designs, the stacked optical antenna and nanopatch antenna are analyzed and their viability for use as a photodiode is evaluated.
The simulation results show that the stacked optical antenna displays poor practicality as a photodiode but the nanopatch design shows an
internal efficiency near 50%. Such a nanopatch diode based on InGaAs is fabricated and tested experimentally to evaluate the diode design.
- Click HERE to see the project poster.
Undergraduate Researcher: Forrest Laskowski
Major: Chemistry and Computer Science
Home Institution: Carroll College
Research Project: Quality Assurance of Electrostatic MEM Relays - Radiation Hardness
Faculty Host: Tsu-Jae King Liu
Graduate Student Mentor: Rhesa Nathanael
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: As electrostatic MEM relays have the potential to solve power density issues related to current MOSFET technology,
it has become ever more important to examine device reliability. Not only true of applications on earth, MEM devices likely promise to
reduce overhead power consumption aboard spacecraft. Thus this paper provides a brief history of radiation hardness in MEM devices.
The experimental effects of radiation on device performance are then examined and device degradation is discussed.
Finally the efficacy of this technology for industry, in the near future, is gauged.
- Click HERE to see the project poster.
Undergraduate Researcher: Stephen Meckler
Major: Chemistry
Home Institution: Penn State University
Research Project: Material Based Exploration of Ferroelectric Negative Capacitance - The Case of PbTiO3
Faculty Host: Sayeef Salahuddin
Graduate Student Mentor: Asif Khan
UC Berkeley Department: Electrical Engineering and Computer Science
Project Abstract: The potential of ferroelectric (FE) lead titanate (PbTiO3, PTO) as negative
capacitance material was investigated. Atomically smooth epitaxial FE PTO-dielectric SrTiO3 bilayer
heterostructures were grown using pulsed laser deposition. Structural and electrical characterization
of the samples were performed using the state-of-the-art X-ray diffraction techniques and impedance analyzer. Room temperature electrical charactteization reveals that PTO/STO bilayers outperform previously
studied crystals by expressing negative capacitance at lower temperatures. The temperature dependence of
capacitance was also studied. These results are promising in the future of energy efficient CMOS technologies,
where insulating films can be replaced with ferroelectric thin films to achieve operating voltages lower than
the classical limit of 60 mv/decade.
- Click HERE to see the project poster.
Undergraduate Researcher: Maja Jennifer Oblepias
Major: Chemical Engineering
Home Institution: Contra Costa College
Research Project: Graphene Synthesis via Mechanical Exfoliation and Characterization with AFM
Faculty Host: Junqiao Wu
Postdoc Mentor: Cheng-Lun Hsin
UC Berkeley Department: Materials Science and Engineering
Project Abstract: Mechanical exfoliation via adhesive device was used to synthesize graphene.
The fabrication of graphene samples was limited to the available equipment to be used.
An optical microscope was used to find acceptable graphene samples. The samples were then
characterized via atomic force microscopy. Graphite sheets were successfully separated to
thin layers of graphenes. However, the area of the graphene fabricated was not controlled.
The mechanical exfoliation process produced graphene flakes with small-area of various sizes and
thickness in a very feasible and economically convenient way.
- Click HERE to see the project poster.