A5009583526- Semiconductor Quantum Structures and Devices
- Semiconductor materials and interfaces
- ZnO doping and properties
- Chalcogenide Semiconductor Thin Films
- Advanced Semiconductor Detectors and Materials
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Quantum Dots Synthesis And Properties
- Silicon Nanostructures and Photoluminescence
- Silicon and Solar Cell Technologies
- Silicon Carbide Semiconductor Technologies
- Perovskite Materials and Applications
- Ga2O3 and related materials
- Electrochemical Analysis and Applications
- Molecular Junctions and Nanostructures
- Aluminum Alloys Composites Properties
- Magnetic and transport properties of perovskites and related materials
- Categorization, perception, and language
- Surface Chemistry and Catalysis
- Advanced NMR Techniques and Applications
- Surface and Thin Film Phenomena
- Copper Interconnects and Reliability
- Quantum and electron transport phenomena
- Language, Metaphor, and Cognition
- Inorganic Fluorides and Related Compounds
University of East Anglia
2023-2024
United States Naval Research Laboratory
2009
Naval Research Laboratory Center for Bio/Molecular Science and Engineering
2009
Purdue University West Lafayette
2004-2007
Low temperature wavelength-modulated reflectivity measurements of isotopically engineered $\mathrm{ZnO}$ samples have yielded the dependence their A, B, and C excitonic band gaps on isotopic masses Zn O. The observed is analyzed in terms gap renormalization by zero-point vibrations via electron-phonon interaction volume mass. A simplified, two-oscillator model, employed analysis, yields renormalizations gaps,...
Abstract The extent to which languages share properties reflecting the non-linguistic constraints of speakers who speak them is key debate regarding relationship between language and cognition. A critical case spatial communication, where it has been argued that semantic universals should exist, if anywhere. Here, using an experimental paradigm able separate variation within a from languages, we tested use demonstratives—the most fundamental frequent terms across languages. In n = 874 29...
Cubic (3C) silicon carbide (SiC) epilayers grown on Si substrates by chemical vapor deposition, characterized using transmission electron microscopy (TEM), high-resolution x-ray diffraction (HRXRD), and Raman spectroscopy, reveal the presence of biaxial in-plane strain. Defect (stacking faults, twins, dislocations) distributions revealed TEM are correlated with peak widths obtained from HRXRD measurements shifts zone center longitudinal optical phonon line. showed defect densities decreasing...
The temperature dependence of the $A$, $B$, and $C$ excitons ZnO, observed in modulated reflectivity spectra $^{68}\mathrm{Zn}^{18}\mathrm{O}$ $^{\mathit{nat}}\mathrm{Zn}^{\mathit{nat}}\mathrm{O}$ range $10--400\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, reveal superposition band-gap renormalization originating electron-phonon interaction volume changes associated with thermal expansion (or) isotopic composition combination anharmonicity. At low temperatures, natural ZnO reach limiting values...
Resonant enhancement enables the discovery and delineation of spin-flip Raman scattering (SFRS) from free or donor-bound electrons in diluted magnetic semiconductors containing $3d$ transition-metal ions at doping concentrations. In such studies, intrinsic g factor host, CdTe present case, has to be accounted for accurately. The SFRS yields conduction band electron $\ensuremath{-}1.676\ifmmode\pm\else\textpm\fi{}0.007$ displays two resonance peaks mediated by excitons, respectively....
Photoluminescence and wavelength-modulated transmission spectra displaying phonon-assisted indirect excitonic transitions in isotopically enriched $^{28}\mathrm{Si}$, $^{29}\mathrm{Si}$, $^{30}\mathrm{Si}$, as well natural $\mathrm{Si}$, have yielded the isotopic mass $(M)$ dependence of gap $({E}_{gx})$ relevant phonon frequencies. Interpreting these measurements on basis a phenomenological theory for $(\ensuremath{\partial}{E}_{gx}∕\ensuremath{\partial}M)$, we deduce...
Raman electron paramagnetic resonance (Raman-EPR) of the transitions due to spin flip $3d$ electrons ${\mathrm{Cr}}^{+}$ in ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}\mathrm{Te}$ and ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}\mathrm{Te}$ is observed at $\ensuremath{\hbar}{\ensuremath{\omega}}_{PM}=g({\mathrm{Cr}}^{+}){\ensuremath{\mu}}_{B}\mathrm{B}$ with $g({\mathrm{Cr}}^{+})=2.0041\ifmmode\pm\else\textpm\fi{}0.0095$ $2.0039\ifmmode\pm\else\textpm\fi{}0.0093$, respectively....
The ${E}_{0}^{\ensuremath{'}}$ direct transition of Si between its valence band maximum $({\ensuremath{\Gamma}}_{8}^{+})$ and conduction minimum $({\ensuremath{\Gamma}}_{6}^{\ensuremath{-}})$ the ${E}_{1}$ along ⟨111⟩ are studied in isotopically enriched $^{28}\mathrm{Si}$, $^{29}\mathrm{Si}$, $^{30}\mathrm{Si}$ employing photomodulated reflectivity. Their energies $({E}_{G})$ at low temperature found to increase with increasing isotopic mass $(M)$ according...
Reversible conductance switching in single quinone-modified oligo(phenylenevinylene)s (OPV) was studied using electrochemical scanning tunnel microscopy. The achieved through oxidation/reduction the quinone moiety of molecule. strong electron delocalization reduced hydroquinone-OPV structure resulted high-conductance state, whereas weaker oxidized quinone-OPV responsible for low-conductance state. ratio conductances measured to be excess 40.
Single crystals of Cd1−xCaxTe and Cd1−yCaySe ternaries, grown by the Bridgman technique characterized microprobe x-ray techniques, showed upper limit x y to be 0.05. The excitonic energy gap, determined from derivative signature free excitons in wavelength modulated reflectivity, shows a linear increase with increasing Ca2+ concentration both ternary alloys. near-band gap emissions donor-bound acceptor-bound observed photoluminescence, investigated as function alloy composition, reveal blue...
3C-SiC p-type epilayers were grown to thicknesses of 1.5, 3, 6 and 10 μm on 2.5° off-axis Si(001) substrates by chemical vapor deposition (CVD). Silane propane used as precursors. Structural analysis was performed using transmission electron microscopy (TEM), high-resolution x-ray diffractometry (HRXRD), Raman spectroscopy. TEM showed defect densities (stacking faults, twins dislocations) decreasing with increasing distance from the SiC/Si interface lattice mismatch stress is relaxed. This...
The Van Vleck paramagnetism of ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}\mathrm{Te}$, a diluted magnetic semiconductor, is explored with electronic Raman spectroscopy an internal transition ${\mathrm{Fe}}^{2+}$, on the one hand, and spin-flip scattering (SFRS) from donor-bound electrons, other. Zeeman splitting nonmagnetic ground state to first excited displays patterns consistent energy levels responsible for paramagnetism. SFRS, in turn, delineates characteristic features...
The indirect excitonic band gap is determined at liquid helium temperatures in isotopically enriched 28Si, 29Si, 30Si, as well natural Si, from a combined study of photoluminescence and wavelength‐modulated transmission. analysis the results on basis phenomenological theory yielded parameters renormalization due to zero‐point motion.