Showing papers on "Cathodoluminescence published in 1981"
Journal Article•
129 citations
TL;DR: In this article, the effect of 30 keV electron beam irradiation on the mobility of α-dislocations in n-GaAs was investigated at temperatures between 290 K and 470 K under a shear stress of 40 MN/m2 using a scanning electron microscope with cathodoluminescence mode.
Abstract: Influence of 30 keV electron beam irradiation on the mobility of α-dislocations in n-GaAs has been investigated at temperatures between 290 K and 470 K under a shear stress of 40 MN/m2 using a scanning electron microscope with cathodoluminescence mode. The effect of electron irradiation (0.39 A/m2) is equivalent to a temperature rise of 80–180 K in the testing temperature range, which is not explained by a heating effect of the lattice by the irradiation. The activation energy of the dislocation motion is decreased from 0.95 eV to ~0.24 eV by the irradiation. The effect is explained in terms of recombination-enhanced glide of dislocations.
64 citations
TL;DR: In this paper, the structural properties of double-heterostructures and multiquantum-well structures were investigated by scanning transmission electron microscopy, and the results indicated that the higher quantum efficiency of MQW is correlated with dislocations originating in the substrate.
Abstract: Undoped double‐heterostructures (DH) and multiquantum‐well structures (MQW) grown by molecular beam epitaxy are studied by cathodoluminescence and photoluminescence. Their structural properties are established by scanning transmission electron microscopy. In DH discrete nonradiative centers are observed with densities ∼104–105 cm−2; some of them are correlated with dislocations originating in the substrate. In sharp contrast, MQW show a very uniform luminescence with no nonradiative action at dislocations. These results might explain in part the higher quantum efficiency of MQW grown by molecular beam epitaxy.
56 citations
TL;DR: In this article, Monte Carlo calculations are used to compute the generated electron-hole pair distribution and the electron beam induced current in order to determine the minority carriers diffusion lengths when an electron beam probes a semiconductor specimen in the neighborhood of a p-n junction.
Abstract: Monte Carlo calculations are used to compute the generated electron–hole pair distribution and the electron beam‐induced current in order to determine the minority carriers diffusion lengths when an electron beam probes a semiconductor specimen in the neighborhood of a p‐n junction. It is shown that with direct band‐gap semiconductor materials, such as GaAs, the current generated by the reabsorbed recombination radiation must be taken into account. Its contribution can be evaluated by comparison with the cathodoluminescence signal. Three GaAs devices of different doping level are checked. Plots of computed induced current versus probe position for a GaAs p‐n junction are presented.
39 citations
TL;DR: In this article, the intensity of YAG, activated with rare-earth ions, shows a nonlinear behavior as a function of incident current density under electron bombardment, and it is shown that nonlinearity effects, in cases where temperature quenching can be excluded, are caused by saturation of the excited state population.
Abstract: The intensity of luminescence in YAG, activated with rare‐earth ions, shows a nonlinear behavior as a function of incident current density under electron bombardment. Tb3+ or Eu3+ activated samples exhibit deviation from linearity at input power densities exceeding 104 W/m2, while Ce3+ luminescence is linear up to the highest power densities studied (108 W/m2). It is shown that nonlinearity effects, in cases where temperature quenching can be excluded, are caused by saturation of the excited‐state population. The results are interpreted in a model which also takes into account excited‐state absorption within one activator and energy transfer between neighboring activator ions.
38 citations
TL;DR: In this paper, it was reported that similar cathodoluminescence spectra are excited by an electron beam striking BaTiO3, SrTiO 3 and TiO2 ceramics at room temperature.
Abstract: It is reported that similar cathodoluminescence spectra are excited by an electron beam striking BaTiO3, SrTiO3 and TiO2 ceramics at room temperature. The energy location of the luminescence bands does not depend on various doping or reduction treatments. The luminescence intensity increases with the electron beam current as well as with the conduction electron density. The luminescence is interpreted as a fundamental transition of local character in the TiO6 octahedron; the conduction electrons localized at the Ti sites in polaron states recombine with the 0–2p valence electron defects. The shape and energy location of the luminescence spectra are qualitatively in accordance with an explanation in terms of a configuration coordinate model.
35 citations
TL;DR: In this paper, the authors interpreted a macroscopic manifestation of microscopic interactions between glide dislocations on these octahedral slip planes and the dislocation of the mosaic, whereby passage of fresh gliders through low-angle boundaries and forest deformation has produced jogs which have persisted since the deformation.
Abstract: Dislocation cathodoluminescence exhibiting certain peculiarities in anisotropy of polarization localized in sheets parallel to octahedral planes in a mosaic, semiconducting natural diamond is interpreted as a macroscopic manifestation of microscopic interactions between glide dislocations on these octahedral slip planes and the dislocations of the mosaic, whereby passage of fresh glide dislocations through low-angle boundaries and forest dislocations of the mosaic has produced jogs which have persisted since the deformation.
33 citations
TL;DR: In this paper, the cathodoluminescence of single crystals of Cu In S 2 obtained by iodine chemical transport was studied as grown crystals and crystals annealed in In, S, (In + S), or in vacuum.
33 citations
TL;DR: In this article, the theoretical efficiency for the direct conversion of electrical energy into luminescent emission, that is, electroluminescence (EL), is first evaluated from thermodynamics.
30 citations
TL;DR: In this article, the authors determined the intensity and lifetime patterns of CCL at variable temperatures for wavelengths ≤ 1.1 μm with a time resolution of 4.5 ns in less than 5 min.
30 citations
TL;DR: Growth conditions and properties of AlxGa1-xAs (0.1 ≤ × ≤ O.3) using metalorganic vapour phase epitaxy (MO-VPE) are investigated in this paper.
Abstract: Growth conditions and properties of AlxGa1-xAs (0.1 ≤ × ≤O.3) using metalorganic vapour phase epitaxy (MO-VPE) are investigated. N-type is achieved either by silicon or by selenium doping. Properties of the layers are evaluated by Hall effect, cathodoluminescence and photoluminescence. It is shown that selenium doping leads to luminescent material : when x = O.1, the efficiency is only a factor of 2 smaller than for GaAs. Deposition temperature is a critical parameter : increasing the growth temperature yields more luminescent Alx Ga1-x As.
TL;DR: In this paper, a GaAlAs/GaAs oxide isolated stripe geometry was examined using the cathodoluminescence (CL) and electron beam induced current (EBIC) modes of the scanning electron microscope, and by transmission electron microscopy in a 1-MeV TEM.
Abstract: Qualified GaAlAs/GaAs oxide isolated stripe geometry DH lasers, degraded at temperatures up to 90 °C, have been examined using the cathodoluminescence (CL) and electron beam induced current (EBIC) modes of the scanning electron microscope, and by transmission electron microscopy in a 1‐MeV TEM. The main features observed in the EBIC and CL images in the plane of the heterojunction of the degraded lasers were bright and dark bands running parallel to the stripe, together with brightened mottled regions extending well outside. The separation of the bands and the extent of the mottled region is dependent on the width of the stripe. This general pattern is modified considerably near to the facets of the lasers. Calculations of strain profiles for the different laser types suggested that these phenomena can be explained in terms of a model of operation induced, strain enhanced, defect migration. Small dislocation loops seen at the edges of the stripe, using transmission electron microscopy appear to support th...
TL;DR: In this article, the cathodoluminescence (edge emission) of single crystals of CuInS2 obtained by iodine chemical transport has been studied and the ionization energy of impurities involved has been calculated.
Abstract: We have studied the cathodoluminescence (edge emission) of single crystals of CuInS2 obtained by iodine chemical transport. Emission intensity as a function of excitation, temperature, and time [time resolved spectroscopy] allow us to reveal donor‐acceptor transitions. By fitting the TRS spectra, we calculate the ionization energy of the impurities involved: EA,D≃45 meV, ED,A ≃95 meV, as well as the maximum transition probability: WMAX≃108 s−1.
TL;DR: In this paper, the authors used transmission electron microscopy and the scanning electron microscope to study indented MgO single crystals and to relate luminescence emission and defect structure.
Abstract: Transmission electron microscopy and the cathodoluminescence mode in the scanning electron microscope have been used to study indented MgO single crystals and to relate luminescence emission and defect structure. Color images of cathodoluminescence indentation rosette have been also obtained. Marked differences in the emission and the defect structure in different areas of indentation have been found and in particular a high density of defects have been observed in the center of indentation including some defects which seem to be characteristic of this region.
TL;DR: In this paper, the perfection of homoepitaxial layers grown on highly S−, Zn− and Sn−doped InP substrates by liquid phase epitaxy has been evaluated by etch pitting and transmission cathodoluminescence.
Abstract: The perfection of homoepitaxial layers grown on highly S‐, Zn‐ and Sn‐doped InP substrates by liquid phase epitaxy has been evaluated by etch pitting and transmission cathodoluminescence. It is shown that high‐quality layers, which are macroscopically dislocation free over large areas, can be grown on the S‐doped substrates. The situation regarding the epitaxial layers deposited on the Zn‐doped substrates is complex. The transmission cathodoluminescence study reveals, in addition to dislocations, areas with poor luminescence within the epitaxial layers. Furthermore, the quality of thin layers (∼2 μm thick) grown on the Zn‐ and Sn‐doped substrates is better than that of the thick layers (∼10 μm).
TL;DR: In this article, the authors used the half-width of the cathodoluminescence peak of p-type InP to determine carrier concentration and inhomogeneities in the material.
Abstract: Cathodoluminescence studies were carried out on p‐type InP having carrier concentrations ranging from 7.2×1016 to 7.4×1018 cm3 in the temperature range of 80–580 K. It was found that low‐temperature spectra exhibited peaks at 1.41 and 1.38 eV. These peaks were attributed to band‐to‐band and band‐acceptor transitions, respectively. The dependence of the band‐to‐band peak on temperature was used to extend knowledge of the temperature dependence of the energy gap of InP to 550 K. It was shown that the half‐width of the cathodoluminescence peak can be used for the determination of carrier concentration and carrier‐concentration inhomogeneities in the material. The variations of the cathodoluminescence peak height with temperature indicated the possibility of Auger recombination for high carrier concentrations (7.4×1018 cm3) at temperatures above 450 K.
TL;DR: In this article, a scanning electron microscope (SEM) with the cathodoluminescence (CL) was used to observe dislocation motion on the specimen surface of IIb-VIb semiconducting compounds (CdS and CdTe).
Abstract: Continuous observation of dislocation motion on the specimen surface of IIb–VIb semiconducting compounds (CdS and CdTe) has been made using a scanning electron microscope (SEM) with the cathodoluminescence (CL) by use of a deformation apparatus installed in the SEM chamber. With the application of stress, SEM-CL patterns revealed an increasing density of dark spots that formed dark stripes along slip traces. For both CdS and CdTe crystals, regardless of the slip system involved, the dark spots corresponding to individual dislocations appeared in the SEM field without displaying their moving state and seldom disappeared, indicating that dislocations are immobilized after they travel a certain distance from the source with a high velocity. The investigation of slip-band growth in CdS showed that screw bands on the basal plane exhibit the photoplastic effect, whereas those on the prismatic plane do not, in accordance with the macroscopic deformation tests.
TL;DR: In this paper, the bluish green cathodoluminescence of ZnS:Ce, Li has been investigated while varying the firing temperature, Ce and Li concentrations.
Abstract: The bluish-green cathodoluminescence of ZnS:Ce, Li has been investigated while varying the firing temperature, Ce and Li concentrations. Bright luminescence of Ce3+ is obtained only when the samples are quenched from a temperature higher than 1000°C in a sulfur atmosphere containing Li. The optimum concentration of Ce is 5×10-5–10-4 g. atom/mol. The Li concentration should be higher than that of Ce for efficient luminescence. The maximum energy conversion efficiency of the as-quenched samples is about 12%. The luminescence efficiency is greatly decreased by heat-treatment at temperatures below 900°C, probably because of segregation of Li ions. Noble metals and other Ia elements are not such efficient sensitizers as Li for Ce3+ luminescence.
TL;DR: In this article, the doping behavior of S and Se in the VPE growth of GaAs at 760 and 660°C is studied by carrier concentra-tion, mobility, photo and cathodoluminescence measurements.
Abstract: The doping behaviour of S and Se in the VPE growth of GaAs at 760 and 660°C is studied by carrier concentra-tion, mobility, photo and cathodoluminescence measure-ments. The carrier concentration increases linearly with the partial pressure of S or H2Se up to a solubi-lity limit, the highest value of which is obtained with Se at about 1019cm-3. The mobility for Se-doped layers is higher than for S-doped ones when n > 4.1017cm-3, and a mobility decrease is observed for both at dopings exceeding the solubility limit. Postgrowth annealing at the growth temperature of highly doped samples decreases their carrier concentration to values corresponding to the bulk solubility limit. The decrease of the room temperature luminescence intensity at high doping levels in tentatively interpreted as due to precipitate for-mation. Finally, the linear dependence on the dopant partial pressure of the impurity incorporation as well as the observed annealing behaviour are interpreted by an incorporation mechanism controlled by the surface states.
TL;DR: In this article, the emission spectra of zinc telluride single crystals implanted with zinc, argon or aluminum ions were measured and the emission bands centred near 580 nm were observed.
TL;DR: Cathodoluminescence and fluorescence microscopy have been used to study vasogenic edema in experimentally induced brain tumors in rats and are suited for the demonstration of FITC- or TRITC -coupled antiserum, and thus allow the evaluation of serum protein extravasation.
Abstract: Cathodoluminescence and fluorescence microscopy have been used to study vasogenic edema in experimentally induced brain tumors in rats. Both methods are suited for the demonstration of FITC- or TRITC-coupled antiserum, and thus allow the evaluation of serum protein extravasation. Cathodoluminescence is more time consuming and laborious than fluorescence microscopy, but it has distinct advantages: Contrast enhancement improves the differentiation between certain cell types, and the higher resolution of the scanning electron microscope allows the identification of subcellular regions which cannot be recognized by conventional fluorescence microscopy.
TL;DR: In this paper, the possibility of the occurrence of laser phenomena in the DCEL of thin films of ZnS:Cu:Nd:Cl, designed for display purposes, has been investigated.
TL;DR: In this article, the effects of 300K implantation of 200-keV Cd+ ions and subsequent pulsed laser annealing in GaAs were investigated by means of depth-resolved cathodoluminescence at 80 K.
Abstract: The effects of 300‐K implantation of 200‐keV Cd+ ions and subsequent pulsed laser annealing in GaAs were investigated by means of depth‐resolved cathodoluminescence at 80 K. We found that lattice order could be restored sufficiently to increase the implanation‐quenched luminescence by 2–3 orders of magnitude with either ruby or Nd:glass lasers. Thus the luminescence is recovered to within an order of magnitude of that in unimplanted material.
TL;DR: The use of transmission cathodoluminescence (TCL) as a nondestructive screening technique for rake lines in (Al, Ga)As double heterostructure laser material is reported in this article.
Abstract: The use of transmission cathodoluminescence (TCL) as a nondestructive screening technique for rake lines in (Al, Ga)As double heterostructure laser material is reported here for the first time. TCL evaluation is shown to correlate well with the fraction of good devices for both broad area and stripe geometry laser configurations.
TL;DR: In this paper, phase diagrams of the systems CuGaS2-CdX2 (X=Cl, I) were determined by weight loss measurements and differential thermal analysis.
Abstract: Phase diagrams of the systems CuGaS2-CdX2 (X=Cl, I) were determined by weight loss measurements and differential thermal analysis. Both systems show eutectic behaviour. By flux growth needle- or rod-like crystals having {101} and {112} faces and its axis parallel to the direction were obtained. This crystal morphology can be explained accounting for the difference in the I–VI and III–VI bond strengths. Cathodoluminescence spectra are measured on both as-grown and annealed crystals.
TL;DR: In this article, the authors reveal the excitation mechanisms of activator ions by irradiation of electron beam on phosphor crystals, and suggest a possible model that radiative recombination of electron−hole pairs only occurs at the activator ion showing two valences at the ordinary conditions.
Abstract: It has been shown that the concentration dependence curve of activator luminescence provides us with a powerful tool in studying cathodoluminescence. The experimental results reveal the excitation mechanisms of activator ions by irradiation of electron beam on phosphor crystals; two excitation mechanisms should be considered: (i) direct excitation by incident electrons, including internally generated secondary electrons; and (ii) indirect excitation through the mobile electron and holes generated by incident electrons. The experimental results also suggest a possible model that (iii) radiative recombination of electron‐hole pairs only occurs at the activator ions showing two valences at the ordinary conditions, and (iv) the type of radiative recombination process at the activator ions is determined by the type of carrier which is first trapped.
TL;DR: In this article, it was observed that the number of rows of a cathodoluminescence rosette is a factor of two lower than that for the etch pit one.
Abstract: The (111) plane of MgO single crystals was deformed by a concentrated load. It was observed that the number of rows of a cathodoluminescence rosette is a factor of two lower than that for the etch pit one. The explanation of this phenomenon is given. The polarity of plastic deformation was revealed using both an etch pit technique and cathodoluminescence method. It is shown that deformation causes a change of the cathodoluminescence spectra. The spectra, obtained from crystal deformed by indentation and from compressed crystal, are similar.
[Russian Text Ignored].
TL;DR: In this paper, the authors analyzed the cathodoluminescence of cinnabar powder which emission appears as a broad band peaked at 1.65 eV at liquid helium temperature.