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Virtual assistants (VA) like Siri, Alexa, or Google Assistant are becoming household names - especially for families with young children. Scientific inquiry studying this user population and their intention to use VAs at home, however, remains scarce. By bridging the Technology Acceptance Model, Uses and Gratifications theory, and the first proposition of the Differential Susceptibility to Media Effects Model, this study disentangles (1) different types of families with (2) different motivations for (3) different forms of VA-usage (i.e., parent only, child only, co-use). Cross-sectional survey data (N = 305) from Dutch parents with at least one child between 3 and 8 years and a Google Assistant-powered smart speaker in their home show that (1) families mostly differ along parents' digital literacy skills, frequency of VA-use, trust in technology, and preferred degree of child media-mediation. (2) Hedonic motivation is key for parents to (3) co-use the VA together with their child(ren). New pathways for the methodological and theoretical study of technology use in families are highlighted. Developers can best anchor VA-application among families in aspects of enjoyment while scholars and policy makers might wish to consider additional meaningful intervention criteria for the future study and guidance of family VA-use practices.

A growing world population requires sufficient food to sustain itself. Therefore, increasingly more resources are required to produce the food. Insects are a viable food and feed alternative since their production requires only a fraction of the resources that conventional livestock needs. For the efficient production of insects, automation technology is needed. An automatic monitoring of the insects’ growth ensures stable production processes and a high product quality. The use of a camera with image processing using neural networks makes it possible to detect insects, measure their features such as shape and colour and enables to derive their age, size, and health. In this paper, instance segmentation using mask scoring regional convolutional neural network (Mask Scoring R-CNN) shows good results in detecting house crickets (Acheta domesticus). A dataset is created consisting of six images, showing 1,022 insect instances, of a real-world cricket production facility to train and test the algorithm. Furthermore, image augmentation by cropping, flipping and rotating is applied to the set to solve the problem of limited data. By combining the augmentations, 288 different trainings are compared to find the best augmentation strategy. The evaluation of the algorithm uses two variations of the F1-score: one variation to estimate the capabilities of producing qualitative segmentation masks and another to estimate the detection capabilities. For the estimation of the detection capabilities, a rule termed ‘centre over ground truth’ is developed. The results show that the presented method is suitable for monitoring a cricket production facility with a recall of 76.6% and a precision of 96.2%.

Inhibition is one of the key processes that regulate working memory (WM) activity. The main research question concerned the nature of inhibition of highlighted information in WM. The study was desi...

The main research problem is the differentiation of the state of attention during convergent and divergent tasks. Divergent tasks are associated with creative processes. These tasks require varied and often new solutions. It is necessary then to activate, in the working memory, information poorly connected to the long-term memory network. The key process in activating information in memory is attention. A hypothesis was that divergent tasks are performed with greater extensiveness of attention than convergent tasks. The research procedure used in the conducted experiment was based on the simultaneous execution of the extensive attention test and a convergent task (recalling the remembered melody) or a divergent task (improvisation based on the remembered melody). The results support the hypothesis. Creative processes depend on the state of attention and its active application. Głównym problemem badawczym jest różnicowanie stanu uwagi w czasie wykonywania zadań konwergencyjnych i dywergencyjnych. Zadania dywergencyjne wiązane są z procesami twórczymi. Zadania te wymagają różnorodnych i często nowych rozwiązań. Niezbędne jest wówczas aktywowanie w pamięci roboczej informacji słabo połączonych z siecią pamięci długotrwałej. Kluczowym procesem w aktywowaniu informacji w pamięci jest uwaga. Postawiona została hipoteza mówiąca, że zadania dywergencyjne są wykonywane przy większej ekstensyfikacji uwagi niż zadania konwergencyjne. Procedura badawcza wykorzystana w przeprowadzonym eksperymencie opierała się na jednoczesnym wykonywaniu zadania konwergencyjnego (odtwarzania zapamiętanej melodii) lub dywergencyjnego (improwizacja w oparciu o zapamiętaną melodię), przy jednoczesnym rozwiązywaniu testu mierzącego ekstensywność uwagi. Uzyskane wyniki wspierają postawioną hipotezę. Procesy twórcze zależą od stanu uwagi i jej aktywnego działania. Przedstawione w artykule badanie zostało przeprowadzone w ramach zadania badawczego „Psychologiczne aspekty wykonawstwa muzycznego”, finansowanego przez Akademię Muzyczną w Krakowie.

Background Cortical regions that support cognitive control are increasingly well recognized, but the functional mechanisms that promote such control over emotional and behavioral hyperreactivity to alcohol in recently abstinent alcohol-dependent patients are still insufficiently understood. This study aimed to identify neurophysiological biomarkers of maintaining abstinence in alcohol-dependent individuals after alcohol treatment by investigating the resting-state EEG-based functional connectivity in the cognitive control network (CCN). Methods Lagged phase synchronization between CCN areas by means of eLORETA as well as the Barratt Impulsiveness Scale (BIS-11) and Beck Depression Inventory (BDI) were assessed in abstinent alcohol-dependent patients recruited from treatment centers. A preliminary prospective study design was used to classify participants into those who did and did not maintain abstinence during a follow-up period (median 12 months) after discharge from residential treatment. Results Alcohol-dependent individuals, who maintained abstinence (N = 18), showed significantly increased lagged phase synchronization between the left dorsolateral prefrontal cortex (DLPFC) and the left posterior parietal cortex (IPL) as well as between the right anterior insula cortex/frontal operculum (IA/FO) and the right inferior frontal junction (IFJ) in the delta band compared to those who later relapsed (N = 16). Regression analysis showed that the increased left frontoparietal delta connectivity in the early period of abstinence significantly predicted maintaining abstinence over the ensuing 12 months. Furthermore, right frontoinsular delta connectivity correlated negatively with impulsivity and depression measures. Conclusions These results suggest that the increased delta resting-state functional connectivity in the CCN may be a promising neurophysiological predictor of maintaining abstinence in individuals with alcohol dependence.

BACKGROUND Bullous pemphigoid (BP) is a distressing autoimmune bullous disease strongly associated with severe pruritus; however, data concerning pruritus in BP are still scarce. No clinical research evaluating the effect of BP on sleep quality has been conducted. AIM To evaluate the intensity of pruritus measured by nocturnal wrist movements (NWMs) and the sleep quality in patients with BP using actigraphy in comparison with nonpruritic healthy controls (HCs) with subsequent correlations with an itch visual analogue scale (VAS) as a subjective measure, disease severity [Bullous Pemphigoid Disease Area Index (BPDAI), urticaria/erythema, erosions/blisters] and serum total IgE level. METHODS In total, 31 patients with newly diagnosed BP (mean ± SD age 75.4 ± 12.3 years) and 40 nonpruritic HCs (age 73.5 ± 11.7 years) were recruited. All participants wore a sleep monitor (ActiSleep+) on the dominant wrist. RESULTS For patients with BP, median VAS score was 5.5 and median BPDAI was 43 (urticaria/erythema BPDAI was 16, erosions/blisters BPDAI was 29). Scratching, defined as bouts of NWMs, was significantly (P

The fragmented ecosystems along the Niagara Escarpment World Biosphere Reserve provide important habitats for biota including lichens. Nonetheless, the Reserve is disturbed by dense human populations and associated air pollution. Here we investigated patterns of lichen diversity within urban and rural sites at three different locations (Niagara, Hamilton, and Owen Sound) along the Niagara Escarpment in Ontario, Canada. Our results indicate that both lichen species richness and community composition are negatively correlated with increasing human population density and air pollution. However, our quantitative analysis of community composition using canonical correspondence analysis (CCA) indicates that human population density and air pollution is more independent than might be assumed. The CCA analysis suggests that the strongest environmental gradient (CCA1) associated with lichen community composition includes regional pollution load and climatic variables; the second gradient (CCA2) is associated with local pollution load and human population density factors. These results increase the knowledge of lichen biodiversity for the Niagara Escarpment and urban and rural fragmented ecosystems as well as along gradients of human population density and air pollution; they suggest a differential influence of regional and local pollution loads and population density factors. This study provides baseline knowledge for further research and conservation initiatives along the Niagara Escarpment World Biosphere Reserve.

Pre-service music teacher preparation is based on theoretical and practical classes. During practical classes, it is impossible to practice particularly difficult situations or to experience long-term, controlled influence on the educational and motivational processes in the classroom. Playing Motivation in Learning Simulation (MiLS) game, a student of the Academy of Music in Krakow (player) is tasked with running a small class of virtual students for five months. During this time, the player's actions affect the work and social behavior of virtual students. The player can make mistakes and observe consequences, which is not possible during practical classes in a real school. Each player leads a group of 4 virtual students. The game is aimed at achieving three goals, (1) building a student music quartet (social goal), (2) getting the highest level of efficiency and knowledge (cognitive goal - preparing students for the concert) and (3) maintaining or increasing students' involvement in future music activities (motivational goal). During the MiLS game, the player receives feedback on the level of efficiency and motivation of virtual students. Each decision made by the player has a specific impact on cognitive, motivational and social parameters in the virtual classroom. The described game is in the testing phase at the Music Academy in Krakow.

Now, as never before, young people are surrounded by media—thanks to the sophistication and portability of the technology that puts it literally in the palms of their hands. Drawing on data and empirical research that cross many fields and continents, authors Valkenburg and Piotrowski examine the role of media in the lives of children from birth through adolescence, addressing the complex issues of how media affect the young and what adults can do to encourage responsible use in an age of selfies, Twitter, Facebook, and Instagram. This important study looks at both the sunny and the dark side of media use by today’s youth, including why and how their preferences change throughout childhood, whether digital gaming is harmful or helpful, the effects of placing tablets and smartphones in the hands of toddlers, the susceptibility of young people to online advertising, the legitimacy of parental concerns about media multitasking, and more.Patti M. Valkenburg is a university distinguished professor of media, youth, and society at the University of Amsterdam. Jessica Taylor Piotrowski is associate professor of youth and media entertainment at the University of Amsterdam.

The accessibility of the lateral line system and its amenability to long-term in vivo imaging transformed the developing lateral line into a powerful model system to study fundamental morphogenetic events, such as guided migration, proliferation, cell shape changes, organ formation, organ deposition, cell specification and differentiation. In addition, the lateral line is not only amenable to live imaging during migration stages but also during postembryonic events such as sensory organ tissue homeostasis and regeneration. The robust regenerative capabilities of the mature, mechanosensory lateral line hair cells, which are homologous to inner ear hair cells and the ease with which they can be imaged, have brought zebrafish into the spotlight as a model to develop tools to treat human deafness. In this chapter, we describe protocols for long-term in vivo confocal imaging of the developing and regenerating lateral line.

The kinetics of 4H-SiC thermal oxidation by RTP technique and the properties of thin thermal oxide was reported. The thickness of the thermal oxide was determined by spectroscopic ellipsometry and confirmed by electrical measurements. The conductance method was applied to analyse the surface states parameters. The lifetime, density and cross-section of the surface traps were extracted for as-fabricated MOS capacitors and after thermal annealing processes.

In this work, a method based on simple geometrical considerations is proposed for a more accurate measurement of the quantum dots (QDs) diameter. For this purpose actual QD dimensions from atomic force microscope images and the radius of the probe tip are only necessary. The method is used to characterize self-assembled InAs/GaAs QDs prepared by molecular beam epitaxy (MBE), which exhibited a bimodal size distribution. Accepting the approximate spherical canopy QD shape and the similar coefficient of the relationship p = r/h for two groups of QDs with different sizes, one obtains the value of the tip radius and diameters of the QDs in the plane of nucleaction.

The technology of neutron transmutation doping of silicon wafers in MARIA nuclear research reactor is described. The studies of the radiation defects performed with positron annihilation confirmed that divacancies dominate in the irradiated material. Thermal treatment of irradiated silicon at 700-1000°C produces void - phosphorus complexes and void aggregates. The resistivity of the samples produced by neutron transmutation doping was found to be uniform within 2.5% limits. The severe reduction of the minority carrier lifetime in irradiated samples was confirmed.

Photoelectric voltage distribution on mc-Si wafers subjected to phosphorus gettering processes was investigated. It was demonstrated, that the measured photoelectric voltage results from bulk photovoltaic effect and photoelectric voltage connected with potential barriers occurring on grains boundaries. It was shown that sample illumination results in reduction of bulk photoelectric effect enabling better visualization and investigation of potential barriers. Relations determining photoelectric voltage distribution on single barrier are given. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Benedicks thermovoltage resulting from non-symmetric distribution of temperature gradients for different surface recombinations on sample surfaces has been determined in this paper using non-linear system of transport equations. Density distributions of generalised Price internal current J p , taking into account the excess carrier generation and Γpotential being the measure of charge carrier injection have also been determined. Minority carrier distributions and quasi-fermi levels variations for electron and holes resulting from Fermi level splitting due to thermoinjection have been calculated. Quasi-fermi level variations were used for determination thermo emf values.

In this paper we present the results of study of thin oxide films: CdO, ZnO and RuSiΟ 4 used as transparent ohmic contacts to GaSb/InGaAsSb/AlGaAsSb photodiodes. Thin oxide films with thickness of 50 nm were deposited by magnetron sputtering. CdO and RuSiO 4 were formed in a reactive process in Ar-Ο 2 atmosphere, from Cd and Ru 1 Si 1 targets, respectively. ZnO films were deposited directly from ZnO target by rf sputtering. We have shown that application of CdO, ZnO and RuSiO 4 transparent films instead of conventional metal-based contacts enables to improve of photodiode properties. As a result, GaSb/ InGaAsSb/AlGaAsSb photodiodes with detectivity D* increased by factor of 2 and reduced by factor of 3 the series resistance were obtained.

The effects of electrochemical treatment in either 21%(NH 4 ) 2 S-H 2 O or 16%Na 2 S-C 3 H 7 OH solutions on the surface properties of GaSb, In 0.23 Ga 77 As 0.18 Sb 0.82 and Al 0.34 Ga 0.66 As 0.025 Sb 0.975 have been investigated by complementary use of Variable Angle Spectroscopic Ellipsometry (VASE) and X-ray Photoelectron Spectroscopy (XPS). We have shown that electrochemical sulphuration enables to produce 94-350 nm thick insulating overcoats with good surface morphology. The main components of the passivating layers are Ga 2 S 3 and Sb 2 S 5 when formed on GaSb, while additional components of In 2 S 3 , admixture of Al 2 O 3 and appearance of Al-As bond were observed on InGaAsSb and AlGaAsSb, respectively. The main feature distinguishing the effect of electrochemical treatment in Na 2 S-C 3 H 7 OH when comparing to those in (NH 4 ) 2 S-H 2 O is that passivating layers contain additional components of Na 2 SO 3 and/or Na 2 SO 4 .

The usefulness of ZrN films as masks for epitaxial lateral overgrowth of GaAs and GaSb by liquid phase epitaxy is studied. It was observed that during the growth process ZrN masks are mechanically stable, they adhere strongly to the substrate and do not show any signs of degradation even at the growth temperature as high as 750 °C. Moreover, perfect selectivity of GaAs and GaSb epitaxy was obtained on ZrN masked substrates ensuring the growth wide and thin layers. To study the influence of growth conditions on electrical resistivity of the mask, ZrN films deposited on GaAs substrates were annealed in various atmospheres. It was found that at temperatures higher than about 580 °C the ZrN masks become highly resistive when heat-treated in hydrogen flow employed during growth. Usually, LPE growth temperature for GaAs is higher. Thus, ELO growth of GaAs by LPE becomes more difficult, though still possible, if ZrN masks are to be applied as buried electrical contacts. For GaSb ELO layers however, typical LPE growth temperature is about 480 °C. This allows us to grow high quality GaSb ELO layers by LPE still preserving high electrical conductivity of ZrN mask. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Fabrication of surface-relief microstructures in GaSb for application in mid-infrared optoelectronic devices is described. Photo- and e-beam lithography was used to define patterns on GaSb surfaces. Ar/O2 sputter etching and RIE in BCl3-based plasma were applied to transfer preshaped master into the GaSb substrate. Circular microlenses with an aspect ratio (height to diameter) 0.4/10 µm and circular gratings with 0.4 µm linewidth / 1 µm period and 1.7 µm depth have been demonstrated.

LPE growth of quaternary Ga 1− x Al x As y Sb 1− y and Ga 1− x In x As y Sb 1− y compounds on (100) GaSb substrates has been investigated for growth temperatures T o =590–594 °C and various amount of supersaturation. Epilayers were characterised by means of XRD, TEM, AFM, EPXMA and SIMS. It has been found that LPE growth at T o ∼593 °C produces good quality single Ga 1− x Al x As y Sb 1− y layers unless the Al content in the melt does not exceed x Al l =0.02 giving perfectly matched Ga 1− x Al x As y Sb 1− y epilayers with Al content in the solid up to x =0.03. Also, smooth and lattice matched Ga 1− x In x As y Sb 1− y layers for indium atomic fraction in liquid up to x In l =0.40 have been grown. For higher In content in the melt quality of layers drops drastically because corresponding composition of such layers are situated near miscibility gap. Our approach to fabrication epilayers with high value of x relies on the use of an additional inter-layer GaAlAsSb, lattice-matched to GaSb, inserted between GaSb and high x index epitaxial layer. With such a procedure we were able to grow smooth and homogeneous Ga 1− x Al x As y Sb 1− y epilayers with Al content in solid x =0.62 and Ga 1− x In x As y Sb 1− y layers with In content of 0.24.

Liquid phase epitaxial lateral overgrowth of GaAs layers on GaAs substrates masked by tungsten films was studied. We show that at our growth conditions perfect growth selectivity was obtained, so the layers started growing from the openings cut in the mask only. However, serious damage of the mask during epitaxial growth was observed. As this deteriorates crystallographic quality of the layers a procedure was elaborated to eliminate degradation of the tungsten film by the melt. In particular, reduction of growth temperature and deposition of Au/Zn wetting layers between tungsten film and the GaAs substrate were found important to avoid degradation of the mask and for successful lateral growth of the layers. Tungsten masked GaAs substrates were then used for lateral overgrowth of GaAs by liquid phase electroepitaxy. Preliminary results are presented showing that application of electrically conductive tungsten mask, which allows a direct DC current flow from the melt to the substrate, results in much wider and thinner electroepitaxial layers than those grown on the substrates coated by insulating film.

The photovoltaic phenomena in inhomogeneous semiconductors are discussed here. (i) The Rooesbroeck potential is generalised and the formulae defining the Tauc bulk photovoltaic effect (BPV), in semiconductors with position-dependent doping, are derived. (ii) The domain of the inhomogeneities is expanded, and besides doping the cases of position-dependent energy gap EG and mobilities in the presence of temperature gradient are described. Thus a new thermo-photovoltaic effect is revealed. (iii) The equations describing the BPV potential distribution in the case of point illumination are derived. Using the Green function formalism the equations are obtained, which give a base to examine the inhomogeneities especially of resistivity distribution. (iv) The method of images is used to calculate the BPV potential distribution. The potential distributions in rectangular plates and circular slices are presented. (v) The results of photovoltaic measurements carried out on a sample with temperature gradient are presented, giving an experimental confirmation of the thermophotovoltaic effect. Application of BPV to determine experimentally resistivity distribution is demonstrated. (vi) The theory and measurements of the bulk photoelectromagnetic effect (BPEM) taking place in an inhomogeneous semiconductor exposed to magnetic field are presented.

One of the key parameters determining detection properties of silicon PIN detector structures (pThe paper presents a method for measuring the spatial distribution of effective carrier diffusion length in silicon detector structures, based on the measurement of photoelectric current of a non-polarised structure illuminated (spot diameter of 250 μm) with monochromatic radiation of two wavelengths λ

To investigate local arousal fluctuations in adults who received ICSD-2 diagnosis of somnambulism.EEG neuroimaging (eLORETA) was utilized to compare current density distribution for 4s epochs immediately preceding sleepwalking episode (from -4.0 s to 0 s) to the distribution during earlier 4s epochs (from -8.0 s to -4.0 s) in 20 EEG segments from 15 patients.Comparisons between eLORETA images revealed significant (t4.52; p0.05) brain activations before onset of sleepwalking, with greater current density within beta 3 frequency range (24-30 Hz) in Brodmann areas 33 and 24.Sleepwalking motor events are associated with arousal-related activation of cingulate motor area.These results support the notion of blurred boundaries between wakefulness and NREM sleep in sleepwalking.

The intra- and inter-observer variability in delineation of the parotids on the kilo-voltage computed tomography (kVCT) and mega-voltage computed tomography (MVCT) were examined to establish their impact on the dose calculation during adaptive head and neck helical tomotherapy (HT). Three observers delineated left and right parotids for ten randomly selected patients with oropharynx cancer treated on HT. The pre-treatment kVCT and the MVCT from the first fraction of irradiation were selected to delineation. The delineation procedure was repeated three times by each observer. The parotids were delineated according to the institutional protocol. The analyses included intra-observer reproducibility and inter-structure, -observer and -modality variability of the volume and dose. The differences between the left and right parotid outlines were not statistically significant (p > 0.3). The reproducibility of the delineation was confirmed for each observer on the kVCT (p > 0.2) and on the MVCT (p > 0.1). The inter-observer variability of the outlines was significant (p < 0.001) as well as the inter-modality variability (p < 0.006). The parotids delineated on the MVCT were 10% smaller than on the kVCT. The inter-observer variability of the parotids delineation did not affect the average dose (p = 0.096 on the kVCT and p = 0.176 on the MVCT). The dose calculated on the MVCT was higher by 3.3% than dose from the kVCT (p = 0.009). Usage of the institutional protocols for the parotids delineation reduces intra-observer variability and increases reproducibility of the outlines. These protocols do not eliminate delineation differences between the observers, but these differences are not clinically significant and do not affect average doses in the parotids. The volumes of the parotids delineated on the MVCT are smaller than on the kVCT, which affects the differences in the calculated doses.

Background Abfraction is believed to be caused by biomechanical loading forces. It may be due to flexure and ultimate fatigue of tooth tissues that occur away from the point of occlusal loading. Other possible causes of cervical lesions include toothbrush abrasion and erosion. The purpose of this study was to investigate the characteristics and prevalence of abfraction-like lesions in a population of U.S. veterans. Methods The authors evaluated 103 teeth with noncarious cervical lesions in 32 subjects and characterized them based on the surface on which the lesion was located, history of toothbrush abrasion, size of the lesion, presence of plaque, surface texture, and presence and size of occlusal wear facets. Results Clinical examination revealed that adjacent control teeth had a significantly lower percentage of surfaces with plaque than did teeth with cervical lesions. Control teeth also had significantly less gingival recession than did affected teeth. Seventy-five percent of subjects reported a history of using a firm toothbrush, and 78.1 percent reported using a brushing technique that is known to cause toothbrush abrasion in the affected area. Affected teeth had neither significantly different occlusal wear facets nor occlusal contacts than control teeth. No significant correlations were found between cervical lesion dimensions and facet area. Conclusions Toothbrush abrasion is strongly suspected as contributing to the formation of the majority of wedge-shaped lesions in this group of subjects. A small subset of lesions is thought to have resulted from some other phenomenon. Although the presence or contribution of occlusal stresses in the direct formation of these lesions could not be measured directly, the possibility of abfraction could not be eliminated. Clinical Implications Because the existence of abfraction could not be ruled out in about 15 percent of the cases, teeth with noncarious, wedge-shaped lesions warrant careful occlusal evaluation, with the possible need for occlusal adjustment or bitesplint therapy to treat bruxism.

Photo-voltaic effects are considered for semiconductors in which doping, energy gap and temperature are position-dependent. Formula derived for total current density contains four effects: (1) bulk photo-voltaic effect, (2) photo-voltaic effect resulting from inhomogeneity of mobilities, (3) thermo-photo-voltaic effect arising from combined photoconductivity and thermo-electric effects, (4) Seebeck thermo-electric effect. Numerical results shown in figures present relative values of these effects calculated for Ge–Si semiconductor material.

A detailed experimental and theoretical study of exclusion and accumulation at the l-h contact in cylindrical samples (with a current along the radius) has been carried out. Two types of the second contact have been used: either the same l-h contact or a recombination type ohmic contact. It has been shown that both the inhomogeneous electric field in a cylinder and the high generation-recombination capability of the second ohmic contact at the larger radius enhance the exclusion and accumulation effects near the small-radius contact. This is manifest in lowering the bias voltage needed for a high-level depletion or accumulation, the latter becoming competitive with injection by the excess carrier concentration level. Experimental investigations of non-equilibrium charge carrier distribution in these samples have been implemented by two methods. Along with the well known IR probing technique in the spectral range of free carrier absorption, the thermovision technique, enabling us to visualize the concentration distribution, has been used for the first time. The obtained results are useful for improvement of the far-infrared source and modulator parameters.

The influence of intrinsic stress in silicon wafers during the Czochralski crystal growth process and during technological processing of semiconductor devices on defect distribution and yield was investigated. The determination method of intrinsic defect distribution by applying subtle flatness measurements (GFLT parameter) is proposed. Results of measurements are compared with calculated stress distributions. Defect density distributions measured on wafers subjected to technological processes are related to intrinsic stress distributions and electrical parameters of semiconductor devices.

The influence of Na2S and (NH4)2S treatments on the surface properties of GaSb have been investigated through the etch rate, ellipsometry and Schottky barrier measurements. XRD and TEM analysis were performed to examine the effect of sulfide pretreatment of GaSb substrate on the LPE growth of InGaAsSb/AlGaAsSb heterostructures and their structural quality. Additionally, C–V characteristic of Hg-Schottky barriers were measured to evaluate carrier concentrations in non-intentionally doped InGaAsSb epilayers. Na2S preepitaxial treatment has been applied to LPE growth of n-In0.084Ga0.916As0.086Sb0.914/p-Al0.45Ga0.55As0.02Sb0.98 LED heterostructures for λp=2.06 μm and n-In0.23Ga0.77As0.18Sb0.82/p-Al0.24Ga0.76As0.02Sb0.98 PD heterostructures for wavelength λ=2.0–2.4 μm. As a result, LEDs which with increased by a factor of 4 quantum efficiency and total power of 6 mW were obtained. Mesa-structure photodiodes were characterised by detectivity D ∗ λ=2.2 μm =4×1010 cmHz1/2 W−1 at room temperature and dark current density jd=16 mA/cm2 at a reverse bias of −0.5 V.

The bonding quality of silicon wafers used in SOI technology, [1] was estimated by the application of infrared transmission measurements. The investigated wafers were directly welded at high or low temperature by using an intermediary layer. Uniform and extended radiation source was applied. The intensity of the radiation transmitted through the wafer was recorded by the thermovision camera scanning the sample. The proposed way of the experiment, enabled very fast transmission visualization of the entire wafer surface and rough estimation of bonding quality. The more exact analysis of the geometric parameters of the measurement set-up and transmissions of ideal and real semiconductor wafers shown below, enabled in some cases the determination of the sort and size of defect occurring between the bonding wafers.

We report on the RIE etching of GaSb, AlGaAsSb and InGaAsSb materials in CCl 2 F 2 and CCl 4 plasmas diluted with either H 2 or N 2 . The highest etch rate (∼2 μm/min for GaSb) was achieved with CCl 4 /N 2 chemistry, however, with an important degree of selectivity in etching of GaSb and quaternary alloys. By contrast, CCl 4 /H 2 plasma enables anisotropic etching of heterostructure materials at an etch rate of ∼0.2 μm/min. CCl 2 F 2 -based plasma exhibited very slow etch rates (≤100 nm/min) and high selectivity in etching of GaSb over AlGaAsSb. The obtained results were applied in patterning of micrometer-size circular and stripe mesas in photonic GaSb/InGaAsSb/AlGaAsSb device structures, as well as in the fabrication of submicron circular gratings in GaSb.

Experimental values of the polarization of the low-temperature luminescence from the VGaSnGa and VGaSiGa complexes in n-GaAs under conditions of resonant excitation by polarized light propagating along the [110] or [100] crystal axis are compared with expressions obtained in the classical dipole approximation for defects with triclinic or monoclinic symmetry. It is shown that the rotator fraction in the superposition of rotator and oscillator contributions to the emission of the complexes is 17–18%. The direction of the axis of these dipoles, which matches the experimental data, is consistent with the assumption that the effect of the donor on the vacancy orbitals of a hole localized in the complex is lower than that of the Jahn-Teller effect. The resulting symmetry of the complex may be monoclinic or triclinic. In either case, deviation of the optical dipole axis of the complex from the dipole axis of an isolated VGa vacancy distorted as a result of the Jahn-Teller effect is lower for the VGaSnGa and VGaSiGa complexes than for VGaTeAs complexes. This means that the effect of the donor on the electron structure of the VGaTeAs complexes is greater than in the VGaSnGa and VGaSiGa complexes. This correlates with the difference in the donor position in these complexes.

The paper presents theoretical and experimental investigations of the exclusion and accumulation effects in rectangular p+-p-p+ structures with a homogeneously doped p-region under conditions of a temperature gradient along its base. It is shown that the temperature gradient causes a strong asymmetry of properties, such as current-voltage characteristics, distributions of non-equilibrium carriers and electric field, with regard to polarity of the voltage drop across the base. The results obtained can be useful for the technology of infrared devices working at room temperature as well as for sensors sensitive to the polarity of an electric field.