Eric Seabron, Ph.D. is an assistant professor at Howard University Department of Electrical Engineering and Computer Science. He was born and raised in Baltimore Maryland where he graduated from Randallstown High School. His career began at Morgan State University where he earned a BS degree in Electrical and Computer Engineering in 2013. He received his Ph.D. in Materials Science and Engineering from the University of Illinois – Urbana Champaign in 2017, where he developed novel scan probe characterization methods to study GaAs nanowires and Carbon Nanotubes. After which, he worked for over three years as a Principal Microelectronic Engineer in a semiconductor fabrication laboratory at Northrop Grumman Corporation in Baltimore Maryland. Before joining Howard University, Seabron was a National Research Council Postdoctoral Fellow residing at the U.S. Naval Research Laboratory (Washington, D.C.). from 2020-2021. His research group focuses on 1D/2D nanomaterials growth and devices, Phase Change Chalcogenide Metamaterials, reconfigurable microwave/RF electronics, and polariton physics of hyperbolic optical crystals. His vision for the future is to grow his group to enable high impact research, education outreach, and workforce readiness.
Material Science and Engineering
University of Illinois - Urbana Champaign
2017
Energy and Sustainable Systems Engineering
University of Illinois - Urbana Champaign
2016
Material Science and Engineering
University of Illinois - Urbana Champaign
2015
Electrical Engineering
Morgan State University
2013
Dynamically tunable single-layer VO2/metasurface based THz cross-polarization converter
We demonstrate a single-layer THz metadevice that exhibits cross polarization transmission, a key factor to achieve optical activity. The device is comprised of a two-dimensional array of split ring resonators, each with a vanadium oxide (VO2) pad, integrated into one of the two capacitive gaps of the unit cell. Through numerical investigations we find that as the conductivity of VO2 increases the amplitude of the cross-polarization intensity decreases but maintains a wider broadband range than previously reported for single layered hybrid metamaterial (MM) devices as the VO2 transforms from the insulator to metallic phase. Also the asymmetric transmission, optically modulated by the device, is higher than that of multi-layered MM devices. Due to the materials properties of VO2, our results introduce a promising method that allows for an active sub-cycle dynamic tunability for THz polarization conversion with multiple modalities using optical, electrical or thermal switching. The study is an important step forward in developing compact, integrated, passive and active metadevices for polarization and wavefront control application in the THz.
Understanding carbon nanotubes (CNTs) based electronic devices requires strategies to characterize individual nanotube electronic properties. We will explore a new nonevasive approach to microwave impedance microscopy (MIM) which, we hypothesize, utilizes the ambient water layer as a nanoscale high permittivity medium. This approach eliminates the need for a thin metal oxide surface layer, used in contact mode MIM-AFM of CNTs, which completely obscures resistance mapping and can increase surface roughness by >10×. The potential novelty of our proposed MIM methodology is that the water meniscus, known to form beneath the tip, creates a localized high permittivity environment between the tip and the surface. The materials microwave response image is extracted from the “capacitive difference” observed on trajectories’ measures via the transmission line cantilever during approach. We can mechanically detect the water meniscus formation using AFM force curves while simultaneously mapping resistance, capacitance, and topography. When comparing signal-to-noise (SNR), to contact MIM-AFM, our results suggest a >2× increase in MIM capacitance SNR, 10–100× improvement in MIM resistance SNR, and up to 3× increase in the capacitance mapping resolution by reducing the effects of tip–surface spatial convolution.
Characterization of nanoscale electronic materials using novel methods for scan probe microscopy
In this thesis we will explore several scan probe based microscopy techniques capable of mapping changes in electronic properties with sub-diffraction spatial resolution. Using novel methods for scan probe based microscopy, we combined electrical and morphology mapping to reveal structural driven electrical properties to provide insight into growth physics and electrical transport. We used novel methods for Electric Force Microscopy, Near Field Infrared Microscopy, and Microwave Impedance Microscopy (MIM) to map non-uniform doping and the free carrier distribution in the bulk Gallium Arsenide nanowires. Our results revealed cyclical doping inhomogeneity in regions with morphological defects; we used that information to create a physical model to predicts the impurity distribution along the nanowire. This enables us to better understand the physics behind in situ doping during the growth process.
Selective lateral epitaxial (SLE) semiconductor nanowires (NWs), with their perfect in-plane epitaxial alignment, ability to form lateral complex p–n junctions in situ, and compatibility with planar processing, are a distinctive platform for next-generation device development. However, the incorporation and distribution of impurity dopants in these planar NWs via the vapor−liquid−solid growth mechanism remain relatively unexplored. Here, we present a detailed study of SLE planar GaAs NWs containing multiple alternating axial segments doped with Si and Zn impurities by metalorganic chemical vapor deposition. The dopant profile of the lateral multi-p–n junction GaAs NWs was imaged simultaneously with nanowire topography using scanning microwave impedance microscopy and correlated with infrared scattering-type near-field optical microscopy. Our results provide unambiguous evidence that Zn dopants in the periodically twinned and topologically corrugated p-type segments are preferentially segregated at twin plane boundaries, while Si impurity atoms are uniformly distributed within the n-type segments of the NWs. These results are further supported by microwave impedance modulation microscopy. The density functional theory based modeling shows that the presence of Zn dopant atoms reduces the formation energy of these twin planes, and the effect becomes significantly stronger with a slight increase of Zn concentration. This implies that the twin formation is expected to appear when a threshold planar concentration of Zn is achieved, making the onset and twin periodicity dependent on both Zn concentration and nanowire diameter, in perfect agreement with our experimental observations.
Dr. Eric Seabron, an assistant professor at Howard University Department of Electrical Engineering and Computer Science, likens the difference between quantum physics and Newtonian physics to the difference between an hourglass and a grain of sand.
