Cathodoluminescence (CL) spectroscopy has been used to investigate the irradiation-sensitive defect structure of ultrapure synthetic quartz at 295 and 80 K. CL emissions are identified with particular centers. Insight into processes formation subsequent electromigration resulting from trapped-charge-induced electric field following irradiation by a stationary continuous electron beam presented. The associated either nonbridging oxygen hole center (NBOHC) or trapped-electron...

Cathodoluminescence spectra have been measured to determine the characteristics of ubiquitous green luminescence (GL) in nonstoichiometric zinc oxide (ZnO). Zn- and O-rich ZnO were found exhibit characteristic emissions at 2.53 eV [full width half-maximum (FWHM) 340 meV] 2.30 (FWHM 450 meV), respectively. Hydrogen was used probe physical nature GL centers. The Zn-rich is enhanced upon H incorporation, whereas completely quenched as its underlying acceptor-like ${V}_{\mathrm{Zn}}$ centers are...

ZnO single crystals, epilayers, and nanostructures often exhibit a variety of narrow emission lines in the spectral range between 3.33 3.35 eV which are commonly attributed to deeply bound excitons ($Y$ lines). In this work, we present comprehensive study properties with particular focus on ${Y}_{0}$ transition at 3.333 eV. The electronic optical these centers compared those shallow impurity related exciton binding ($I$ contrast donors ZnO, complexes large discrepancy thermal activation...

Battery-supercapacitor hybridisation enables safe charge-discharge operation at high C rate, up to the supercapacitor capacity, while maintaining battery lifetime. However, battery-supercapacitor systems in parallel connection require a DC/DC converter for voltage balance. Hybridisation material level is explored this study aiming avoid use of converter. Different configurations, hybridised level, are investigated with goal maintain long redox plateau and self-balance without need Applying...

Transmission through dispersive and nonlinear optical fibers produces distortion in subcarrier intensity-modulated systems. Analytic expressions for second- third-order are derived using the time-domain form of field envelope wave equation. The predicted by these agrees well with numerical simulation reasonably experimental data. Significant composite second-order is typical 1.55 mu m cable television systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Abstract Many theoretical and experimental studies deal with the realization of room‐temperature ferromagnetism in dilute magnetic semiconductors (DMS). However, a detailed quantitative understanding electronic properties transition metal doped has often been neglected. This article points out which issues concerning states charge transfers need to be considered using Fe as an example. Methods address these are outlined, wealth data on III–V II–VI compound that have obtained over few decades...

Crosstalk in a two-wavelength 1550-nm standard fiber system at subcarrier frequencies 50-800 MHz is investigated. The dependence of the crosstalk on frequency, wavelength spacing, and optical power measured analyzed. observed attributed to three primary mechanisms: stimulated Raman scattering, cross-phase modulation, Kerr effect combined with polarization-dependent loss. At spacing greater than 9 nm, scattering dominates. less 5 contributor can be polarization dependent loss, except higher...

The influence of ion-beam-produced lattice defects as well H, B, C, N, O, and Si, introduced by ion implantation, on the luminescence properties wurtzite GaN is studied cathodoluminescence spectroscopy. Results indicate that intrinsic produced bombardment mainly act nonradiative recombination centers do not give rise to yellow (YL) GaN. Experimental data unequivocally shows C involved in defect-impurity complex responsible for YL. In addition, C-related complexes appear efficient centers....

The mechanical deformation of wurtzite GaN epilayers grown on sapphire substrates is studied by spherical indentation, cross-sectional transmission electron microscopy (XTEM), and scanning cathodoluminescence (CL) monochromatic imaging. CL imaging indents which exhibit plastic (based indentation data) shows an observable “footprint” deformation-produced defects that result in a strong reduction the intensity emission. Multiple discontinuities are observed during loading when maximum load...

Wurtzite GaN films grown on sapphire substrates are studied by nanoindentation with a spherical indenter. No systematic dependence of the mechanical properties epilayers film thickness (at least for thicknesses from 1.8 to 4 μm) as well doping type is observed. Slip identified one physical mechanisms responsible plastic deformation and may also contribute “pop-in” events observed during loading. visible material cracking found even after indentations at high loads (900 mN), but pronounced...

This work provides a consistent picture of the structural, optical, and electronic properties Fe-doped GaN. A set high-quality GaN crystals doped with Fe at concentrations ranging from $5\ifmmode\times\else\texttimes\fi{}{10}^{17}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}2\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ is systematically investigated by means...

Contact-induced damage has been studied in single-crystal (wurtzite) ZnO by cross-sectional transmission electron microscopy (XTEM) and scanning cathodoluminescence (CL) monochromatic imaging. XTEM reveals that the prime deformation mechanism is nucleation of slip on both basal pyramidal planes. Some indication dislocation pinning was observed No evidence either a phase transformation or cracking samples loaded up to 50 mN with an ∼4.2 μm radius spherical indenter. CL imaging quenching...

We report the phonon deformation potentials of wurtzite GaN and ZnO for all zone center optical modes determined by Raman measurements as a function uniaxial pressure. Despite structural similarities between these two material systems, pressure dependency their vibrational spectra exhibits fundamental distinctions, which is attributed to different bond ionicities. In addition, LO-TO splitting A1 E1 analyzed yields insight into Born’s transverse effective charge eT∗.

The influence of deep level surface defects on electrical and gas sensing properties ZnO nanorods NH3(g) sensors was studied. 50–60 nm in diameter were synthesized via low-temperature hydrothermal growth at 90 °C sapphire substrates. as-grown exhibited a cathodoluminescence (CL) peak centered 1.90 eV (YL), attributed to LiZn acceptors or O interstitials. Subsequent annealing O2 1 atm Zn vapor 650 produced broad CL peaks 1.70 (RL) 2.44 (GL), respectively. RL GL have been ascribed...

Zinc oxide (ZnO) nanoparticles have recently been identified as a promising candidate for advanced nanophotonics applications and quantum technologies. This work reports the formation of luminescent point defects describes their photophysical properties. In particular, it is shown using correlative photoluminescence, cathodoluminescence, electron paramagnetic resonance (EPR), X‐ray absorption near‐edge spectroscopy that green luminescence at 2.48 eV an EPR line g = 2.00 belong to surface...

We present experimental evidence of electron-beam-induced diffusion O and H in unintentionally doped n-type GaN grown on a sapphire substrate. Impurity was investigated using cathodoluminescence kinetics imaging at 4 300 K by wavelength dispersive x-ray analysis. The results illustrate the significance electromigration wide band gap semiconductors, confirm roles ${\mathrm{O}}_{\mathrm{N}}^{\mathrm{\ifmmode\bullet\else\textbullet\fi{}}}$ bound exciton, donor-acceptor pair yellow emissions...

We studied the structural and optical properties of state-of-the-art non-polar bulk GaN grown by ammonothermal method. The investigated samples have an extremely low dislocation density (DD) less than 5 × 104 cm−2, which results in very narrow high-resolution x-ray rocking curves. a c lattice parameters these stress-free were precisely determined using diffraction technique based on modified Bond obtained values are compared to free-standing from different methods sources. observed...

Room temperature single photon emitters are very important resources for photonics and emerging quantum technologies. In this work we study emission from defect centers in 20 nm zinc oxide (ZnO) nanoparticles. The exhibit bright broadband fluorescence the red spectral range centered at 640 with polarized excitation emission. studied showed continuous blinking, however, bleaching can be suppressed using a polymethyl methacrylate (PMMA) coating. Furthermore, hydrogen termination increased...

Zinc gallate (ZnGa2O4) has recently emerged as a promising wide-band-gap material for light-emitting and power electronic devices. This study investigates the impact of cation site inversion on luminescence photocatalytic properties ZnGa2O4. High-quality nanoplates ZnGa2O4 with pure spinel phase, lateral dimensions up to 10 μm, thicknesses around 40 nm are synthesized via hydrothermal reaction. Photoemission Raman spectroscopies reveal significant inversion, where Ga3+ ions occupy...

We present the results of a depth-resolved cathodoluminescence (CL) and transmission electron microscopy study autodoped GaN grown on sapphire. Depth-resolved CL analysis can be used for depth profiling yellow luminescence (YL) center concentration which was found to increase with depth. The are consistent (ON–VGa)2− complex model YL centers [J. Neugebauer C. G. Van de Walle, Appl. Phys. Lett. 69, 503 (1996) T. Mattila R. M. Nieminen, Rev. B 55, 9571 (1996)]. Depth near-edge emission in...

We report theoretical, numerical, and experimental investigations of clipping distortions in CATV systems are reported. The applicability A.A.M. Saleh's (1989) calculation the carrier-to-nonlinear-distortion ratio (CNLD) is extended by incorporating a more precise spectral analysis further analytic results. An effective transfer function model which spectrally resolves distortion at intermodulation products (IMPs) all orders frequencies, features closed-form second- third-order (CSO CTB)...