Characterization Of Deep Levels Research Articles

Beyond Perceived Similarity: Development and Validation of the Character Recognizability Scale (CRS)

ABSTRACT Current understandings of similarity with media characters often focus on visible attributes including gender and race, yet overlook deep-level characteristics such as personality, attitudes, and experiences. In the present research, we address this limitation and develop and validate the Character Recognizability Scale (CRS), which captures different ways in which audiences can recognize themselves in characters. Based on a previous interview study, we formulated 26 scale items. Subsequently, we conducted two studies. In Study 1, we used a sample of 219 university students in the Netherlands to conduct an exploratory factor analysis. We determined the reliability, as well as criterion and convergent validity of the entire scale and the retained factors. In Study 2, we used a sample of 247 respondents in the United States to conduct a confirmatory factor analysis and replicate the results of the reliability and validity analyses. Based on Study 1, we kept 20 items. In both studies, the overall CRS scale as well as its subscales for Personality Recognizability (CRS-p), Attitudinal Recognizability (CRS-a), and Experiential Recognizability (CRS-e) showed a good internal consistency. They also showed criterion validity through an association with perceived similarity. Finally, the CRS and its subscales correlated positively with media engagement and exposure measures, thus demonstrating convergent validity.

From Occasional to Active Crowdshippers: The Significance of Couriers’ Characteristics

German retail customers increasingly demand immediate, flexible, and sustainable deliveries in the urban area. Simultaneously, Germany is characterized by high urbanization, well-developed infrastructure, and a distinct online retail market. Consequently, crowdsourced delivery (CSD) by outsourcing the last-mile delivery to private couriers provides a promising and increasingly acknowledged delivery concept for German cities. Although existing literature has identified attributes that determine crowdshippers’ willingness to take on CSD, research studies lack the attributes’ relevance in combined consideration and their dependence on crowdshippers’ characteristics. A choice-based conjoint analysis with 193 German potential CSD crowdshippers was performed to examine the present research gap. The results reveal delivery time and remuneration as determinant attributes, whereas the degree of familiarity with the recipient and the parcel weight proved less important. In this way, this study is the first to demonstrate the diverging relevance of CSD attributes in the assignment of deliveries. Furthermore, this study proves that the attributes’ relevance is influenced by the crowdshippers’ surface-level and deep-level characteristics. By conducting a sensitivity analysis, this study is the first to determine how the increase in additional travel time affects the willingness to conduct a CSD. Moreover, the influence of the crowdshippers’ familiarity with the recipient on the overall results is low, indicating an application of the concept also used outside of family networks. For CSD platform operators, the results outline how to individualize CSD orders for active crowdshippers to increase their engagement. Policy makers will be informed about how CSD is an opportunity to make transport in the city more sustainable.

(Invited) Towards GaN Passivation: Identification of GaN Surface/Interface States

GaN has been emerging as the next technological semiconductor after silicon and has already secured its superiority in the niche of power electronics with a rapidly growing interest since the advent of electric vehicles. To enable GaN to concur more microelectronic applications, one major barrier has yet to be surpassed. Rather limited control has so far been achieved over the density of GaN interface states. To achieve it, native and process-induced surface states need to be fully identified. Photoluminescence (PL) has been the most commonly used method in the study of GaN defects, and it typically shows a wide sub-bandgap peak centered at 2.2 eV that has been called the yellow luminescence (YL) band. Despite 30 years of studies, the debate as to whether this is a bulk or surface defect has not been settled. Present deep level characterization methods have not provided clear enough evidence. Theoretical studies attempted to associate this luminescence with various bulk defects, e.g., Ga-vacancies, O or O-C complexes,[1] while various optical spectroscopy studies, point to a surface origin.[2]Here, we report results of using an optical spectroscopy method based on surface photovoltage before and after a mild anneal in vacuum. The method is capable of showing the energy distribution of charge density trapped in surface states and thus of monitoring changes thereof. Using the method in air on untreated GaN reveals two peaks over the same ranges of the yellow and blue peaks observed by PL. After a mild anneal at 170 C for 24 hrs in vacuum, the “yellow” charge density peak was absent. Exposure to air was then observed to fully restore the “yellow” charge density peak. This observation clearly points to the involvement of an airborne molecule, a constituent of air, as the source for charge in the yellow-luminescence-related state. If this deep level were a bulk defect, it would not be able to interact with air. This observed interaction with air thus provides a first direct evidence that the yellow luminescence-related defect is a surface state. Experiments of controlled exposure to the various air constituents to identify the related airborne molecule are currently ongoing. The same method is now used in a search for passivation method for this surface state.The method we use is based on the following model. Illumination using sub-band gap photon energies excites electrons from the surface states over the surface potential barrier, consequently, reducing the surface band bending, and this change is observed as photovoltage (Fig. 1). We have already shown how this photovoltage can be used for calculation of the surface charge distribution in GaN HEMT.[3] In the case of bulk crystal, the model is slightly different, and a quantitative relation may be obtained between the measured photovoltage and the surface state charge distribution. Quantitative calculation requires knowledge of the surface band bending in equilibrium, which may not always be reliably obtained. However, when the spectrum is acquired using low photon flux, assuring the change in the band bending is small compared with the equilibrium band bending the surface charge density is practically relative to the derivative of the photovoltage, and thus, qualitative distribution may be obtained.[4]Figure 2 exemplifies the use of the model presented here to obtain a qualitative charge density spectrum. It shows surface charge density obtained using the model from the photovoltage spectrum shown as inset.This method is then used in Fig. 3 to compare three spectra of the same sample: In air (red), in vacuum (green) - the yellow peak is slightly reduced, and after heating up to 450 K for 24 h in vacuum (blue) - the yellow peak is practically gone.These results suggest that the charge in the yellow-luminescence-related state is contributed by a non-inert constituent of air, and this interaction may not be possible unless this state is a surface state. In the talk, preliminary results on the chemical identity of this air constituent will be presented.[1] Van de Walle et al., Microscopic origins of surface states on nitride surfaces, J. Appl. Phys. 101, 081704 (2007).[2] Shalish et al., Yellow luminescence and related deep levels in unintentionally doped GaN films, Phys. Rev. B 59, 9748 (1999).[3] Turkulets et el., Surface states in AlGaN/GaN high electron mobility transistors: Quantitative energetic profiles and dynamics of the surface Fermi level, Appl. Phys. Lett. 115, 023502 (2019).[4] Turkulets et al. The GaN(0001) yellow-luminescence-related surface state and its interaction with air. Surfaces and Interfaces 38, 102834 (2023). Figure 1

No access? No problem! Taking stock of unobtrusive measures for executives’ deep-level characteristics

The deep-level characteristics (e.g., personality, ability, values) of leaders have previously been found to influence key outcomes for followers, organizations, and more. However, many widely used measures of these deep-level characteristics (e.g., self-reported Likert scales) cannot be implemented when studying high-ranking leaders due to a lack of direct access to those types of leaders. In light of this challenge, scholars have developed indirect, unobtrusive measures to capture these deep-level characteristics. In this review, we examine the four overarching approaches prior scholars have used to indirectly measure leaders’ deep-level characteristics—language, visual media, financials, and personal factors—and discuss the strengths and weaknesses of each approach. Based on the patterns found, we also suggest avenues for future research.

Evidence on the homogeneity of personality traits within the auditing profession

Audit firms’ diversity initiatives have focused on enhancing surface-level diversity (e.g., gender and race). While these initiatives serve an important social and business function, we argue that they may not enhance deep-level diversity (e.g., personality traits and thinking styles), creating a gap between rhetoric and reality in terms of deep-level characteristics. We combine critical and positivistic research perspectives to make sense of this rhetoric-reality gap and specifically examine personality trait diversity in audit firms. Focusing on deep-level traits is important because people may appear diverse while thinking and acting similarly. We use data from 981 auditors to examine personality trait diversity using the Five Factor Model: neuroticism, extroversion, openness, agreeableness, and conscientiousness. Our results show a remarkable homogeneity of personality traits for auditors within the same firm type or experience level. We also find important differences within each personality trait. For example, all firm types and experience levels tend to be more homogenous on extroversion and conscientiousness, but more diverse on openness. Taken together, the results suggest that audit firms remain largely homogenous at the personality level, notwithstanding their recent diversity rhetoric and initiatives. These results provide timely evidence to support audit firms’ efforts to re-evaluate and re-consider their diversity, equity, and inclusion efforts.

Matching mentors with mentees

PurposeThis paper aims to review the latest management developments across the globe and pinpoint practical implications from cutting-edge research and case studies.Design/methodology/approachThis briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context.FindingsThe authors found that research on this topic strongly supported matching mentor and mentee based upon individual similarities of deep-level characteristics such as personality traits. They made three recommendations based upon the empirical research on mentorship matching. They offered practical to organizational development practitioners who wish to manage formal mentoring programs.Originality/valueThe briefing saves busy executives, strategists and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

Photon-induced degradation of InGaN-based LED in open-circuit conditions investigated by steady-state photocapacitance and photoluminescence

Degradation of InGaN–GaN LEDs has been the subject of intense investigations in the past few years. While current- and temperature-induced degradation processes have been described, the impact of photon-induced degradation has not been investigated in detail in the literature. This paper aims at improving the understanding of the mechanisms responsible for the degradation of the InGaN subject to high photon densities by stressing the devices under a high-intensity laser beam in open-circuit conditions (i.e., in the absence of external current). We analyzed the degradation by means of electrical, optical, and deep-level characterization techniques. First, we demonstrate the existence of optically induced degradation processes in GaN LEDs: from photoluminescence measurements, we observed a decrease in the luminescence after stress, more prominent in the region irradiated during stress. Second, we ascribe this effect to a decrease in internal quantum efficiency due to the generation of non-radiative defects within the active region. Third, by steady-state photocapacitance measurements, we reveal the presence of a shallow level with an energy of EC–2.2 eV, which can be ascribed to gallium vacancies and its complexes with oxygen and nitrogen and can be related to the increase in yellow luminescence.

Impurity defect absorption and photochromic effect in KNbWO6

In polycrystalline sample KNbWO6 with beta-pyrochlore structure type prepared by solid-state reaction, the diffuse reflection and transmission spectra, as well as the spectral, kinetic, and temperature dependencies of the photochromic effect, have been investigated. The energy characteristics of deep and shallow levels in KNbWO6 band gap have been determined. A model explaining the effect of temperature on the behavior of bleaching kinetics in the photochromic effect was suggested.

The impact of COVID-19 on the European football ecosystem – A Delphi-based scenario analysis

COVID-19 has had a tremendous impact on the world's society and economy. This also applies to European football; the continent's largest professional sports ecosystem has millions of employees in football-related jobs and even more people emotionally attached to the sport. To account for stakeholders' unprecedented level of uncertainty regarding regulatory, economic, social, and technological implications for their business, we systematically examine how COVID-19 will impact the future of the European football ecosystem in the short, medium and long term. We present a Delphi-based scenario analysis with 110 subject matter experts who assessed 15 future projections both on a quantitative and qualitative basis. We find that, for example, a salary cap for players would have the highest impact on the ecosystem, but it is unlikely to be implemented, while an increased awareness for social responsibility would be the most desirable effect of the crisis. To refine the results, we account for surface-level and deep-level characteristics of participants and find significant effects in both cases. We identify three different clusters of projections and discuss the potential threats and opportunities of COVID-19 for the European football ecosystem to contribute to the scientific discussion and to provide guidance for policy- and decision-makers.

EXTENDED MSM METHOD TO ESTIMATE THE REACTIVITY OF A SUB-CRITICAL CORE DRIVEN BY AN ACCELERATOR BASED NEUTRON SOURCE

The Modified Source Multiplication method is used to determine an unknown reactivity level of a reactor from a known one if one has access to the detector counting for both levels when the reactor is fed by a constant neutron source like an Am-Be source. When available, an accelerator driven source, in continuous mode, can be useful as its intensity can be tunable and then adapted to the experimental conditions. However, in that case, the MSM technique must be extended to account for an external source whose intensity, energy and angular distributions can vary from one measurement to another. In this paper, this Modified Multi-Source Multiplication (MMSM) method is applied to measurements done during the FREYA project in the GUINEVERE facility, operated with the GENEPI-3C accelerator providing a mixture of (D,T) and (D,D) neutrons. The monitoring of these sources through the detection of the associated charged particles allows the calculation of the MMSM factors and the estimate of the reactivity values. The results are compared in different configurations with the reactivity obtained with an Am-Be source or in dynamic measurements performed with GENEPI-3C. Their excellent agreement shows the possibility of using such accelerator-based neutron sources for MSM measurements when they are correctly monitored. This is of great interest for deep sub-critical level characterization for which detector count rates per source neutrons might be low.

Characterization of Deep Levels in AlGaN|GaN HEMT by FT-DLTS and Current DLTS

In this work, GaN|AlGaN high electron mobility transistor (HEMT) structures are investigated, grown on semi-insulating SiC substrates by molecular beam epitaxy and metal–organic chemical-vapor deposition techniques. This paper reports on the kink effect and hysteresis effect observed in AlGaN|GaN high electron mobility transistors (HEMTs) on SiC substrate. It is well known that trapping effects can limit the output power performance of microwave HEMTs, which is particularly true for the wide band gap devices. A detailed study is presented of FT-DLTS and CDLTS measurements performed on AlGaN|GaN HEMTs. It is demonstrated that the kink effect is directly correlated to shallow traps, and a remarkable correlation exists between deep levels observed by CDLTS and FT-DLTS and the presence of parasitic effects such as kink and hysteresis effects.

Multiscale Context-Aware Ensemble Deep KELM for Efficient Hyperspectral Image Classification

Recently, multiscale spatial features have been widely utilized to improve the hyperspectral image (HSI) classification performance. However, fixed-size neighborhood involving the contextual information probably leads to misclassifications, especially for the boundary pixels. Additionally, it has been demonstrated that deep neural network (DNN) is practical to extract representative features for the classification tasks. Nevertheless, under the condition of high dimensionality versus small sample sizes, DNN tends to be over-fitting and it is generally time-consuming due to the deep-level feature learning process. To alleviate the aforementioned issues, we propose a multiscale context-aware ensemble deep kernel extreme learning machine (MSC-EDKELM) for efficient HSI classification. First, the scene of the HSI data set is over-segmented in multiscale via using the adaptive superpixel segmentation technique. Second, superpixel pattern (SP) and attentional neighboring superpixel pattern (ANSP) are generated by leveraging the superpixel maps, which can automatically comprise local and global contextual information, respectively. Afterward, an ensemble deep kernel extreme learning machine (EDKELM) is presented to investigate the deep-level characteristics in the SP and ANSP. Finally, the category of each pixel is accurately determined by the decision fusion and weighted output layer fusion strategy. Experimental results on four real-world HSI data sets demonstrate that the proposed frameworks outperform some classic and state-of-the-art methods with high computational efficiency, which can be employed to serve real-time applications.

Deep levels model identification in semiconductor barrier structures

Semiconductor barrier structures are essential elements of modern integrated electronics. The band theory explains properties of barrier structures using deep levels in the semiconductor band gap. The relentless interest in studying the characteristics of deep levels is due to practical needs, ambiguous interpretations and scatters of experimental results obtained by different researchers. In order to increase the accuracy of the measurements, a modified capacitive deep-level transient spectroscopy technic of has been developed. A mathematical model of the hardware transformations of the barrier structure capacitance transient signal is developed and provided in this article. The model considers the nonexponentiality of the capacitance transient and the spectrometer hardware transformations nonlinearity. There are the results of the deep levels experimental studies in silicon diodes and the model parametric identification. The technic makes it possible to reduce by five or more times the six-sigma confidence interval for the discrete deep level activation energy determining in comparison with the round robin test results of ASTM F978-02.

Deep-level diversity in entrepreneurial teams and the mediating role of conflicts on team efficacy and satisfaction

Team start-ups have substantial advantages over solo start-ups, but teams often do not live up to their potential due to conflicts creating unfavorable team dynamics. Based on an experiment with 665 individuals in 133 randomly composed teams participating in a new-venture simulation, we found team members’ deep-level characteristics that trigger motivations to act, i.e., achievement motivation and leadership orientations, to be particularly important sources of task conflicts. We found that diversity in leadership orientation reduces conflicts because not all team members can lead at the same time. Unlike hypothesized, we found that diversity in achievement motivation also reduces conflicts, for which, ex-post, we explore potential reasons. Furthermore, we demonstrate that the mediating task and relationship conflicts differently affect team outcomes due to their different nature of task-relatedness: while task conflicts affect task-related team efficacy and may escalate into relationship conflicts, relationship conflicts directly affect team satisfaction, but not team efficacy. Further emphasizing the importance of a motivational basis of conflicts, we found that individuals’ general self-efficacy, a more belief-related construct, affects team outcomes only through team efficacy, but not via conflicts.

First observation of electronic trap levels in freestanding GaN crystals extracted from Si substrates by hydride vapour phase epitaxy

The electronic deep level states of defects embedded in freestanding GaN crystals exfoliated from Si substrates by hydride vapour phase epitaxy (HVPE) is investigated for the first time, using deep level transient spectroscopy (DLTS). The electron traps are positioned 0.24 eV (E1) and 1.06 eV (E2) below the conduction band edge, respectively. The capture cross sections of E1 and E2 are evaluated to be 1.65 × 10−17 cm2 and 1.76 × 10−14 cm2 and the corresponding trap densities are 1.07 × 1014 cm−3 and 2.19 × 1015 cm−3, respectively. The DLTS signal and concentration of the electronic deep levels are independent of the filling pulse width, and the depth toward the bottom of the sample, evidenced by the fact that they are correlated to noninteracting point defects. Furthermore, Photoluminescence (PL) measurement shows green luminescence, suggesting that unidentified point defects or complex, which affect the optical characterisitics, exhibit. Despite the Si-based materials, the freestanding GaN exhibits deep level characteristics comparable to those of conventional freestanding GaN, suggesting that it is a desirable material for use in the next generation optoelectronic devices with the large-scalibilityand low production costs.

A Social Network Water Army Detection Model based on Artificial Immunity

The wanton dissemination of water army information in social network seriously affects the authenticity of information received by users. With the continuous renewal of the covert means of the water army, the traditional screening means of the water army are no longer efficient. Combined with the idea of computer artificial immunity, this paper deeply analyzes the deep-level characteristics of the water army, finds out the stable and efficient danger and safety signal, calculates its optimal weight matrix through evolution, fuses DCA algorithm to calculate the antigen maturity, and then identifies the water army. The simulation results show that the recognition model based on the immune risk theory has a certain improvement in accuracy and recall rate, while the time cost is greatly reduced, which verifies its effectiveness and high efficiency.

Research on the Problem of Urban Community-based Elderly Care Service under the Background of Aging Population - The Case Study of G City

For tackle the problem of increasing severe aging population, city G started the pilot of Family-Care in communities from 2005, and it has initially formed the pattern of Family-Care in communities with government-directed and standardized operation through the development of the past ten years. However, it still exists some deficiencies. The paper has found the aging population in the G city showing the characteristics of fast, deep level and large amount through analysis of the current situation of aging population and community aged service in G. Although community aged service has obtained some achievements, it also presented the problem of service personnel shortages, low resource utilization rate, short social awareness. To optimize community aged service in G, the paper puts forward some countermeasures and suggestions based on the above research, in order to provide scientific decision-making support for the relevant management department.

Identification of the primary compensating defect level responsible for determining blocking voltage of vertical GaN power diodes

Electrical performance and characterization of deep levels in vertical GaN P-i-N diodes grown on low threading dislocation density (∼104 - 106 cm−2) bulk GaN substrates are investigated. The lightly doped n drift region of these devices is observed to be highly compensated by several prominent deep levels detected using deep level optical spectroscopy at Ec-2.13, 2.92, and 3.2 eV. A combination of steady-state photocapacitance and lighted capacitance-voltage profiling indicates the concentrations of these deep levels to be Nt = 3 × 1012, 2 × 1015, and 5 × 1014 cm−3, respectively. The Ec-2.92 eV level is observed to be the primary compensating defect in as-grown n-type metal-organic chemical vapor deposition GaN, indicating this level acts as a limiting factor for achieving controllably low doping. The device blocking voltage should increase if compensating defects reduce the free carrier concentration of the n drift region. Understanding the incorporation of as-grown and native defects in thick n-GaN is essential for enabling large VBD in the next-generation wide-bandgap power semiconductor devices. Thus, controlling the as-grown defects induced by epitaxial growth conditions is critical to achieve blocking voltage capability above 5 kV.

On the studies of capacitance-voltage-temperature and deep level characteristics of an Au/p-GaTe Schottky diode

This paper deals with the capacitive properties of an unintentionally doped Au/p-GaTe/In Schottky junction. The capacitance-voltage (C-V) measurements are realized at 120–300 K temperature range and also, the deep level characteristics at bulk of p-GaTe are investigated by thermally stimulated capacitance measurement technique (TSC). The C-V measurements yield the C−2 − Vr curves with fairly high correlation at high temperatures. However, the anomaly decreasing of the capacitance values with the temperature is attributed to the ionization of the deep levels which are electrically active at closely 100–270 K temperature ranges. In addition, due to the effect on the measured capacitance curves of the series resistance, the true capacitance characteristics are obtained. The values of barrier height are calculated to be 0.639 eV at 300 K and 1.556 eV at 140 K and it does not follow to the variation of forbidden energy band gap of p-GaTe. In addition, it is seen that the barrier height values from true capacitance curves are the more resolute from the barrier heights of measured capacitance curves. Moreover, the rapid increasing of the barrier height values at low temperatures is only attributed to the effect of the deep levels.

Deep Level Characterization of 5 MeV Proton Irradiated SiC PiN Diodes

In this contribution, we report on the electrical characterization of point defects in 4H-SiC p+in diodes. Ten electrically active levels have been detected in the base region of the devices, by employing Deep Level Transient Spectroscopy (DLTS) and Minority Carrier Transient Spectroscopy (MCTS). Of these ten levels, six are majority carrier traps, in the 0.1-1.7 eV energy range below the conduction band edge, and four were minority carrier traps located in the 0.13-0.4 eV energy range above the valence band edge. We found that, during DLTS measurements, both majority and minority carrier traps can be detected and we explain this by considering the behavior of the quasi-Fermi levels. At last, we studied the impact of proton irradiation on the minority charge carrier lifetime.