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Despite the many expectations of school counselors in responding effectively to crisis situations, there is a lack of research and comprehensive standards that address best practices for school counselors in terms of preparing for and responding to a school shooting. Using federal guidelines and crisis literature, including studies focused on school counselors’ lived experiences of a school shooting, the author offers a research-informed theoretical framework of recommendations at different phases of a school shooting. The framework of recommendations points out probable hindrances to school counselors’ decision making. School counselors’ awareness of these impediments before experiencing each phase of such a crisis would be of benefit to them. School counselors may also use the framework of recommendations to help them assess their developmental needs in relation to preparing for and responding to a school shooting crisis.

We have studied various factors that control the luminous properties of atomic layer epitaxy (ALE) SrS:Ce electroluminescent (EL) devices by using electron paramagnetic resonance, photoluminescent decay, x-ray diffraction, and charge-voltage characterization. EL and PL light is green shifted in ALE SrS:Ce films, compared to powders and thin films prepared with some other techniques. The origin of the green shift is discussed. Moderate heat treatments of as-deposited SrS:Ce devices were found to dramatically improve the EL efficiency. This is due to the removal of defects leading to nonradiative Ce3+ decay and to reduction of Ce4+ to radiative Ce3+. Different heat treatments were found to influence the transferred charge, so that there is an optimal heat treatment temperature between 500 and 750 °C. Heat treatments also induce macroscopic stress in these SrS:Ce films. This was seen to induce a local stress around Ce3+ sites. However, the stresses were not found to directly correlate with the luminous effic...

We demonstrate that extended e-beam exposure produces a contaminating overlayer on phosphors whose opacity increases roughly linearly with time. Raman scattering data and optical analysis indicate that this layer is graphitic in nature, arising from the electron-beam-stimulated conversion of hydrocarbons adsorbed from the vacuum ambient. The presence of this contamination optically attenuates emitted cathodoluminescence, prevents many low energy electrons from ever reaching the phosphor grains, and exacerbates surface charging which reduces the arrival energy of electrons above 1.5–2 keV. All of these effects are shown to impact cathodoluminescent output in an important way, but an accurate accounting of their total impact will be required to assess the importance of other degradation mechanisms like enhanced nonradiative electron-hole recombination at surfaces, both carbon and noncarbon related.

We report results of electron paramagnetic resonance, photothermal deflection spectroscopy, and capacitance‐voltage measurements on amorphous hydrogenated silicon nitride (a‐SiNx:H) thin films exposed to ultraviolet (UV) illumination. It has been previously shown that exposure to UV light activates silicon dangling‐bond defects, i.e., K0 centers, in a‐SiNx:H thin films. Here, we demonstrate that the initially UV‐activated K0 center can be irreversibly annihilated at long illumination times. Because this effect seems to scale with H content of the measured films, we propose that hydrogen may be passivating the K0 defects during the extended UV exposure. We also show that films subjected to long UV exposures trap charge as efficiently as those having much larger K0 concentrations. A few possibilities to explain this effect are discussed.

The electric field emanating from the surface of a poled ferroelectric can control the conduction properties of an overlying semiconducting film; this combination of materials can thus serve as a non-destructive readout, non-volatile memory device. Here we will describe a variety of experimental studies of these devices designed to probe the physics of their operation. The experimental systems included sputtered, n-type semiconductor (SC) films of In2O3 and ZnO deposited on bulk PLZT ferroelectrics (FE) and thin PZT FE films. Two distinctly different types of device response were measured in this study; in the first, the change in SC film conductance observed in the remanent FE state is in the direction expected from the remanent polarization vector in the ferroelectric. In the second, typically seen in thin film FE devices, the opposite behavior is observed. We find that these two general cases of behavior, including the observed variations of the SC film conductances and carrier mobilities, can...

We have measured the optical-absorption properties of plasma-enhanced chemically vapor deposited films of hydrogenated amorphous silicon nitride (a-${\mathrm{SiN}}_{\mathit{x}}$:H) over the energy range from 0.54 to 2 eV using photothermal deflection spectroscopy (PDS). Typical PDS spectra show a broad absorption tail with a large number of narrow absorption peaks. Using the phase sensitive feature of this spectroscopy we are able to separate nitride-related absorption from that arising from the fused quartz substrates. In addition to the broad, featureless band tail, whose magnitude is quite sensitive to optical excitation with light above \ensuremath{\sim}3.9 eV, we observe a number of narrow absorption peaks which are most likely overtones of localized vibrational modes. Specifically, we see peaks at 0.82 and 1.20 eV which we identify as the first and second harmonics of N-H stretching vibrations, and several other peaks whose origins remain undetermined. Prolonged UV excitation produces no detectable change in these vibrational modes, although large changes are seen in the underlying absorption tail. This reinforces previous suggestions that photoinduced changes in these films do not arise from rearrangement of the bonded hydrogen.

Along with the third-order nonlinear susceptibility, χ (3) , the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter for conjugated polymers used in active integrated optical devices. Photothermal deflection spectroscopy (PDS) is an ideal technique for determining the absorption coefficients of thin films of ‘transparent’ materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers, poly(1,4-phenylene-vinylene) (and derivatives) and polydiacetylene-4BCMU, in the spectral region from 0.55 to 3 eV. We find that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1–10 cm −1 . In the region below 1 eV, overtones of C-H stretching modes dominate the absorption behavior. We also observe that irradiation of all of these polymers with light above ∼ 2.5 eV produces enhanced absorption below the fundamental edge. In the absence of light, these excitations decay with characteristic times of 10–1000 s and in some cases they may determine the effective IR transparency in the energy range 1.0–1.8 eV.

Scanning cathodoluminescence (SCL) is a technique that has been widely used to categorize local minority carrier lifetime nonuniformities in bulk and thin film semiconductors. In the case of phosphor powders it has been less popular, partly because the collection and scattering of light generated in an array of particles complicates the extraction of quantitative information about light generation efficiency. Here we demonstrate that by coupling SCL with modern digital imaging manipulation techniques, we can extract quantitative information about the beam energy dependence of phosphor cathodoluminescence with high spatial resolution. A number of common phosphors are examined and a wide range of behavior is observed. We find that materials like ZnS:Ag and SrGa2S4:Eu display uniformly high nonradiative surface energy losses, while other materials like ZnO:Zn have surface losses which are spatially very nonuniform.

UV‐induced enhancement of the subgap optical absorption has been observed in thin films of chemically vapor deposited silicon nitride. The threshold for this process is ∼4 eV. Visible light bleaches out much of the enhanced absorption and 200–400 °C thermal anneals remove the rest, leaving the optical properties of the nitride in the ‘‘as‐grown’’ state. The characteristics of this creation and bleaching process suggest that UV light ‘‘optically dethermalizes’’ the distribution of carriers in localized band tail states. Correlation of our data with recent electron spin resonance results suggests that many of the trapped carriers may be singly occupied silicon dangling bonds.

Electron paramagnetic resonance and capacitance‐voltage studies of hydrogen passivated Si‐SiO2 interfaces indicate that UV irradiation of the interface does not result in the creation of new Pb centers or interface states providing no photocurrent is allowed to pass through the oxide. This is in contrast to the generally known fact that UV irradiation with photoinjection does form interface states.

Our studies of device lifetime and the main degradation mechanisms in Nichia blue LEDs date back to Spring 1994. Following the initial studies of rapid failures under high current electrical pulses, where metal migration was identified as the cause of degradation, we have placed a number of Nichia NLPB-500 LEDs on a series of life tests. The first test ran for 1000 hours under normal operating conditions (20 mA at 23 °C). As no noticeable degradation was observed, the second room temperature test was performed with the same devices but with a range of currents between 20 and 70 mA. After 1600 hours, some degradation in output intensity was observed in devices driven at 60 and 70 mA, but it was still less than 20%. The subsequent tests included stepping up the temperature by 10 °C in 500 h intervals up to a final temperature of 95 °C using the same currents applied in the second test. This work reviews the failure analysis that was performed on the degraded devices and the degradation mechanisms that were identified.

Various optical techniques, including Photothermal Deflection Spectroscopy (PDS), ellipsometry, and transmission measurements, have been used to examine the optical properties of diamond like C films deposited at various laser power densities on Si and fused quartz. The absorption coefficients of these films are typically above 5 × 104 cm−1 throughout the visible part of the spectrum, decreasing quasi-exponentially in the infra-red. Larger sp2/sp3 bonding ratios caused by deposition at lower laser power settings noticeably increase film absorption coefficients. While Tauc plots of our absorption data yield bandgaps of 1.5-1.0 eV, the quality of these fits is unimpressive and the slopes are unphysically low. Rather than modelling these materials as narrow gap semiconductors, we have pursued another avenue: treating the films as a mixture of small graphitic particles embedded in a diamond, sp3-like matrix. We will discuss the results of this approach as well as the evolution of the optical properties after thermal anneals.

Prototype ferroelectric thin film, nonvolatile memory, nondestructive readout (NDRO), semiconductor devices have been fabricated. The “1” and “0” logic states of these prototype devices are in principle determined by the modulation of the conductivity of a semiconductor film channel by the polarization state of the underlying ferroelectric thin film layer. Programmed resistance ratios of the two logic states of 5:1 are demonstrated. While the best performance to date has been achieved for devices that have a 40 nm ln2O3 film covering a 300 nm thick PZT 20/80 layer, we also develop criteria for selecting semiconductor films that will improve performance for this NDRO device design. Among the other semiconductor films that are characterized with respect to this criteria are boron doped Ge, ZnO and aluminum doped ZnO. It is demonstrated that by appropriate donor doping of ZnO films the effects of intrinsic defects are masked and that process temperatures can be extended by 300×C.

Publisher Summary This chapter describes hydrogenation methods, including plasma reactors and directed-ion-beam sources, such as Kaufman and electron-cyclotron-resonance machines. The main drawback of directed-ion-beam sources is the generation of surface damage and of sputtering. Electrochemical techniques are very effective (for example, HF + HN03) and work at room temperature; even immersion in water seems to work. But in all the hydrogenation techniques, the exact nature of the hydrogenation process is still largely a mystery. The chapter presents a discussion on the key features of each method that controls both hydrogenation efficiency and accompanying side effects, such as material erosion and lattice damage. The chapter discusses the production of atomic hydrogen species in gaseous and liquid environments. Because of the high density of hydrogenic species available in electrolytes, the hydrogenation of semiconductors by electrochemical techniques would appear to be an attractive alternative to the gas phase methods.

Recently, photonic lattice structures have become available that are fabricated from refractory materials such as tungsten and thus stable in vacuo at high temperatures. Such structures can be tailored to exhibit optical properties that are not achievable with ordinary optical materials. In particular, photonic lattices can be designed to suppress thermal emission in undesired spectral regions, and can thereby enhance the overall energy efficiency of emission at useful wavelengths. We report measurements of the thermal emission spectra of tungsten photonic lattices in the wavelength range 3to24μm. Suppression of thermal emission at wavelengths longer than the photonic bandedge (∼6μm) is observed, along with significant emission at shorter wavelengths. We show that from 404to546K the spectral emissivity E(λ) is temperature independent and approaches [1−R(λ)], where R(λ) is the measured specular reflectance spectrum. These results are in accord with Kirchhoff’s law.

The primary purpose of this study was to identify any significant relationships between a measure of faculty interest in counseling activities (PAICT) and nine selected student advising experiences. The research setting was a community college of 12,047 students. A stratified, random sample of full-time faculty was selected to complete the PAICT measure, and a cluster random sample of their students were used to obtain self-reported experiences of the advising activities. Only 11% of the variance was accounted for between the faculty PAICT scores and the self-reported advising experiences of their students. There was 17% of the variance accounted for between faculty PAICT scores and eight personal characteristics of their students. The findings indicate that the faculty interest in advising does not affect the way students are advised.

We have examined the optical absorption and spin‐resonance signal characteristics of thin layers of silicon damaged by an abrasive process at room temperature. We find an Urbach‐like dependence of the subgap absorption and a g=2.0055 isotropic spin‐resonance signal characteristic of silicon dangling bonds. Changes in the optical and spin‐resonance data caused by thermal anneals in air, or in atomic hydrogen, indicate that direct electronic transitions of the dangling bond defect are not responsible for the observed optical‐absorption spectra. The doping level dependence of these spectra is consistent with the hypothesis that electronic transitions arising from disorder‐induced band‐tail states cause the subgap absorption.

Significant progress in the understanding of the structural and electrical properties of semiconductor grain boundaries has been made in the last ten years. Much of this work was stimulated by promising technological applications of poly crystalline semiconductors, such as cheap solar cells ( 1 ), large area device arrays for display use (2), integrated circuit gates and interconnections (3), and voltage-controlled resistors (varistors) (4). In addition to industrial research support for these studies, government funding in this area has been readily available. A large part of this interest has focused on polycrystalline silicon, not only because of its attractiveness for many of the above-mentioned uses, but also because it is the best characterized, purest semiconductor available, which allows the researcher to concentrate on grain boundary rather than bulk properties. While this review mainly focuses on this material, it will become clear that many of the concepts discussed can be (and have been) carried over quite successfully to model grain boundary properties in other semiconducting materials. The organization of the text is straightforward; it logically follows the concepts needed to understand the rather complex properties of a given piece of polycrystalline silicon. However, as will become apparent to the reader, our present, somewhat incomplete level of understanding in this area was not acquired in the same simple order that is presented here. While grain boundaries affect the mechanical and chemical properties of silicon in important ways, their major effect-and the one that most influences the operation of the devices mentioned above-is on the

Summary A case of fatal homologous serum hepatitis occurring in a 3-month-old infant seventy-three to seventy-seven days following the administration of whole blood and pooled plasma is reported. The symptoms of the prodromal period were gastrointestinal in type with diarrhea and vomiting but without jaundice. The terminal stage was sudden in onset with jaundice, multiple hemorrhages, and central nervous systems manifestations.

THE PROVOCATIVE food test is a deliberate intracutaneous injection of a potent food extract of sufficient quantity and strength to provoke a mild systemic reaction, followed by the immediate injection of weaker or stronger dilutions of the identical antigen to relieve the provoked symptoms. The test, therefore, consists of two phases: (1) to provoke symptoms and (2) to relieve the induced symptoms. The provocation and the relief of symptoms demonstrate a dramatic cause and effect relationship. The technique described for provocative testing and treatment for foods was developed by Carleton H. Lee, MD. His original work was on provocative testing for foods; he subsequently developed provocative testing for inhalants. This paper will deal solely with foods. A second paper will describe the provocative testing and treatment technique for inhalants. Both Dr. and Mrs. Lee suffer from food and inhalant allergies. Their symptoms were poorly controlled by serial dilution antigen titration

Electrically active defects in edge‐defined film‐fed grown silicon ribbon solar cells have been passivated using a hydrogen plasma from a Kaufman ion source. Significant improvements in solar cell efficiency for both low diffusion length starting material (∼20 μm) and high diffusion length (∼50 μm) material have been obtained. For the former, passivation has produced solar cell efficiency improvements as high as 41% and in the case of the latter, solar cell efficiencies as high as 14.5% (AM1) have been obtained. Electron beam induced current micrographs are shown which indicate near total defect passivation for at least the top 9 μm of the solar cell.

Despite the fact that lattice imaging studies have shown that grain boundaries in group IV semiconductors often have structures which are complicated and inhomogeneous on the scale of tens-tohundreds of angstroms, simple theories assuming uniform double depletion layers have recently been shown to successfully predict many of the majority carrier transport properties of these defects. On the other hand our knowledge of the interaction of grain boundaries with minority carriers is in a considerably more primitive state. I will describe recent attempts to understand the effects of illumination on grain boundary potential barrier heights and the influence of these defects on the optically generated minority carrier population. Quantifying this latter interaction is particularly important in estimating the performance of polycrystalline solar cells. Simple but elegant scanned excitation measurements for measuring s, the minority carrier recombination velocity at grain boundaries, will be reviewed. I will discuss recent measurements of s as a function of temperature and illumination intensity and show how these data can be correlated with zero-bias impedance measurements.

Photoinjection of electrons into silicon dioxide in metal-oxide-semiconductor (MOS) capacitors with 3.5 eV light is shown to create interface states with no apparent hole trapping precursor. The creation rate of these interface states depends strongly upon whether injection is from the gate metal or the silicon substrate, and on the forming gas annealing sequence used to passivate growth-induced interface states. A mechanism involving electron-induced release of hydrogen in the oxide is consistent with some aspects of the data.

This report describes the progress to date with high voltage gas switching using the DQ switch developed by Pulsar Associates, Incorporated. Self-breaking operation has been achieved at 4 million volts and 800 kiloamperes. Triggered operation has been achieved at 2 million volts. The control of insulator tracks is described, along with the engineering of the switch. (Author)

Grain boundaries play an important role in determining the operating characteristics of devices such as varistors and thin film solar cells and transistors. In the last several years detailed one-electron expressions have been developed for the transport coefficients of majority and minority carriers at grain boundaries. These theories have been successful in predicting the measured electrical properties of bicrystals in lightly doped silicon. The status of our understanding in this area will be reviewed in some detail. Recent extensions of these calculations which have been necessary to explain measurements on grain boundaries in degenerately doped GaAs will also be reviewed.

THE PROVOCATIVE inhalant test is a deliberate intracutaneous injection of a potent inhalant extract of sufficient quantity and strength to provoke a mild systemic reaction, and the immediate injection of weaker (or, occasionally, stronger) dilutions of the identical antigen to relieve the provoked symptoms. Lee's experience with foods led him to believe that provocative testing for inhalants was feasible and would be of distinct value in testing and treatment, especially when the patient failed to show improvement with serial dilution antigen titration technique. Provocative inhalant testing is done for house dust, molds, animal danders, and the pollens of trees, grasses, and weeds. Atmospheric contaminants vary with seasonal changes. In inhalant-sensitive patients, sensitivities will show great variations with seasonal change and pollen toxicity. Foods can be controlled in the diet, but inhalants cannot be controlled by the patient. It is the opinion of the senior author that provocative testing and

Adrenalectomized dogs maintained on desoxyeorticosterone acetate developed a fatal circulatory collapse when given normal dog plasma. They showed general restlessness, a rapid fall in blood pressure and cardiac index, a decline in central venous pressure and general prostration. Most dogs developed a bloody diarrhea and a minority showed edematous swelling of the face with itching. Animals with intact spleens exhibited marked hemoconcentration, splenectomized animals did not. Blood and plasma specific gravity determinations offered no evidence for gross plasma loss. Diphenhydramine prevented the collapse.