Materials Science and Engineering/Doctoral review questions/Professors

Research

 * optical fibers
 * smart fibers
 * sense heat, light, molecules
 * create transistors
 * advisor is the ISN director
 * created smart thin films
 * combine many materials classes
 * need materials that melt together congruently
 * poster in hallway

Favorite orals topics

 * DOS
 * Fermi Function
 * Maxwell's Equations
 * Multilayers
 * OLED

Research
"Our research concentrates on integrating previously incompatible materials to create new functionality in electronic and optoelectronic components and systems. In semiconductor materials, understanding and accommodating differences in lattice constant, atom valence, and thermal expansion are key to producing new substrates and heterostructures. Our work has already had important commercial impact on the areas of strained Si for high-performance, low-power digital electronics and high-efficiency, low-weight solar cells for space applications. Furthermore, we have fabricated the first commercially promising lasers and visible light-emitters on Si, which will impact future electronic and optoelectronic systems. Finally, we are incorporating thin film battery materials into Si-based fabrication, ultimately leading to a truly integrated "system on a chip" with components for power supply and management, wireless communication, optical communication, and high-speed digital computation.
 * Nanowires
 * GaP
 * Si
 * Thin films
 * MOCVD
 * gallium phosphide
 * SiGe
 * buffer layers to grow any III-V compound
 * integrate InP
 * strained silicon
 * Statement on website:

"Current projects include: Selective defect nucleation in H+-implanted semiconductor layers for improved layer-transfer applications; fabrication of new substrates such as GOI, SSOI, SGOI, and SSOS through relaxed buffer bonding; growth and fabrication of high-mobility strained-SiGe MOSFETs for CMOS applications; controlling threading dislocation density (TDD) in SiGe graded buffers for integration of III-V devices on Si; growth of high-quality InGaAs graded buffers on GaAs for HEMT electronics and telecommunications applications; visible AlInGaP LEDs and lasers integrated on Si and GaAs; basic studies concerning the generation, propagation, and interaction of point, line, and planar defects in these heterostructures."

Favorite orals topics

 * band gap versus lattice parameter
 * phase diagrams
 * strained silicon
 * compound semiconductors
 * trends in terms of properties, price
 * apply a hydrostatic pressure
 * force wavefunction overlap
 * electrons ejected
 * insulator formed
 * could function as a metal after wavefunction overlap
 * unit cell doubles
 * two atom system
 * Pierels distortion

Classes Taught

 * 3.225
 * Half semester version of 3.23

Research

 * Semiconductor nanowires grown by MOCVD
 * Quantum confinement effect (1D material)
 * High lattice mismatch
 * InGaN: indium segregates
 * difficult to cause light emission
 * substrate: sapphire
 * nanowire system: easier
 * thin film: defect is minimized to strain relaxation
 * grow without dislocations
 * GaAs, AlGaAs, GaN (expand)
 * nitrogen is very inert
 * control the stoichiometry
 * critical range of temperature
 * HEMT, LED (InGaN), lasers (GaAs, AlGaAs), EGMT (alternate MOSFET), thermal electrics (term paper - nanowires good phonon scattering)
 * issue with laser: reflectivity of ends and electrically pump
 * heterostructures
 * core-shell structures
 * pseudobinary systems
 * MOCVD
 * arsene (AsH3)
 * ammonia (NH3)
 * neutral (N2): can't decompose
 * Specialist in cathode luminescence in TEM

Favorite orals topics

 * LED
 * Device of physics question

Research

 * Waveguide in silicon
 * amorphous materials
 * create with lift-off
 * complicated compound
 * resonator
 * use optical ways to sense
 * small change in the absorption
 * absorption frequency will change
 * Integrate photonics
 * Optical devices
 * Active devices
 * Strained germanium (3.43 and 3.44)
 * Silicon based light emitter
 * Silicon embedded devices
 * Higher recombination coefficient
 * hard to inject electricity with insulator present
 * premature
 * investigating the field
 * Raman laser
 * silicon: pump at 1.1 eV and supply the phonons
 * Raman provides the phonon
 * Silicon based solar cells
 * high efficiency
 * quantum wells

Favorite orals topics

 * Photonics
 * Silicon waveguide
 * System on a chip
 * Questions may be from a unique perspective

Classes taught

 * 3.46 (OCW)
 * Focus in fundamentals
 * Trends in periodic table
 * Different processing techniques
 * Low concentration of defects
 * How to produce high quality films
 * Device
 * Optical
 * Germanium
 * Figures of merit

Personality

 * not overbearing
 * soft-spoken

Research

 * Tight-binding simulations

Favorite orals topics

 * Quantum mechanics
 * E vs. k
 * Similar to Fick's questions

Favorite orals topics

 * Fundamentals
 * MOS
 * Density of states
 * quantum well laser and non-quantum well laser
 * E vs. k

Personality

 * nice person

Favorite orals topics

 * Not necessarily magnetics questions
 * Ion implanation
 * Diffusion
 * Oxidation
 * Tight binding
 * Crystal properties of GaAs
 * CZ growth of Si
 * Electromigration
 * Atomic potentiatial versus atom separation (electron orbitals)
 * Electron tunneling

Classes Taught

 * Fall 2006 3.155J Microelectronics Processing Tech.
 * Spring 2007 3.022 Microstructural Evolution
 * Spring 2007 3.024 Electronic Properties

Research
a. hard magnetic materials such as the rare earth CoSm series, b. soft amorphous materials such as the FePB type, c. small particulates such as found in magnetic tape, and d. ferromagnetic shape memory alloys.
 * Simulations
 * Magnetisms
 * Research in the following fields:

Favorite orals topics

 * TMR
 * Capacitor topics
 * Magnetic energy storage
 * Electrical energy storage
 * Broad questions

Research

 * Magnetic memories
 * GMR effect to create device
 * Multilayer
 * Self-Assembly with block polymers
 * Phase separation (3.44)
 * Use templated transfer
 * Periodic magnetic films
 * Find a silicon or GaAs material that is electroptic
 * Stable output of laser
 * Fardly effect
 * magneoptically active material
 * must be a ferromagnetic material
 * Light can be rotated clockwise
 * Use two polarizers of different size
 * Principle of polarization
 * Polarization of the electrons
 * In oxides
 * Molecular orbital mechanism
 * Different energies
 * Electron jumping
 * Permittity tensor
 * Off-diagonal components
 * Electric field in the material
 * Anisotropy permeability
 * Kerr effect
 * Velocity is different
 * Second-order non-linear effect
 * Difference in the traveling speed of the different components

Favorite orals topics

 * Clear, brief questions

Classes taught

 * Undergraduate

Personality

 * nice

Research

 * Porous alumina
 * Template to create carbon nanotubes
 * Multiwall
 * Inerted pyramid created by interference lithography
 * Dewet the Ni film
 * Self-assembly of gold nanoparticle
 * Electromigration
 * Minimize diffusion on the surface
 * SiN using plasma enchanced CVD
 * Thiol of polymer can bond into the copper
 * Use polymer to coat
 * Coat the copper with polymer
 * Electromigration on the surface
 * Can also implement with gold
 * Deposit Ni films
 * Buffer layer

Favorite orals topics

 * Rate limiting steps
 * Thermo more than quantum
 * Si and Ge (bandgaps, devices)
 * MOSFET characteristics
 * BJT characteristics
 * SiGe (wafers, thin films, quantum wires, quantum dots)
 * evaporative deposition
 * amorphous vs. poly vs. epitaxial films
 * cellular/dendritic growth
 * Sn

Research

 * Quantum confinement effect
 * Surface measurement with AFM and TEM
 * Optical applications
 * Waveguide
 * "Investigation of the structure-property relationships that exist between nanostructured molecular assemblies and their surface properties"

Research

 * Full cells and sensors
 * micro fuel cells
 * electrode
 * solid state devices
 * mixed ionic and electronic conduction
 * both in a fuel cell
 * ionize whatever is flowing across
 * oxygen conducting
 * charge
 * conduct electrons
 * Y stabilized Zr
 * Ce
 * f-orbital
 * unusual applications
 * defect chemistry
 * ZnO
 * reaction of gas throughout the thickness
 * Operated at low temperature
 * Chemiosorption and desorption
 * Fundamental aspects
 * Impedance spectroscopy
 * Measure the complex impedance
 * See the resistance
 * Different capacitance at grain boundary
 * Schottky contact
 * Through the air and between electrodes
 * Thermoelectric effect
 * Use Prof. Ross
 * DC and RF sputtering
 * why sputtering is useful

Favorite orals topics

 * Ampeometric
 * Focus on fundameals
 * Device properties
 * Columns III, IV, V
 * Defect chemistry
 * Research in full cells and sensors
 * Refractory materials
 * Electronic applications
 * Materials used as a temperature compensated sensor
 * Compensate: zero temperature of resistance

Personality

 * Clarify the question
 * open-ended
 * direct
 * approachable
 * would like direct answers

Research

 * Superconducting
 * Microstructure
 * Transmission
 * Magnetic field
 * Ceramics
 * Small particles generated by combustion

Research
No research group
 * Point defects
 * Isotopes to use with tracers

Favorite orals topics

 * Crystal structure of a particular element (interstitials, symmetry, etc.)
 * Diffusion
 * Magnetization versus applied field (Hysteresis loop)
 * Effective mass

Classes

 * 3.60: Structure