Structural and optical behaviors of 2D-layered molybdenum disulfide thin film:Experimental and ab-initio insights

The two-dimensional (2D) layered molybdenum disulfide (MoS2) material represents a nominee potent for optoelectronic devices application. In this research work, the experimental characterizations of 2D- MoS2 thin films are reported in terms of various microscopic and spectroscopic techniques. The synthesized MoS2 thin films are grown by employing the pulsed laser deposition (PLD) procedure on SiO2/Si substrates. In order to monitor the deposition rates of ablated films, the buffer argon-gas pressures are varied during the pulsed laser deposition at substrate temperature of 700 °C. The field emission scanning electron microscopy and atomic force microscopy analyzes revealed a change in the surface morphology of MoS2 films when the buffer Ar-gas pressure is varied between 0 and 100 mTorr. For all samples, a 2H-phase is revealed from X-ray diffraction patterns, indicating a reflection (2θ) around 14.85°. By varying the deposition pressure of laser-ablated MoS2 films, the X-ray photoelectron spectroscopy divulged the chemical compositional elements and valence states of Mo and S on the surface of MS2 films with low density of defects. Analysis of the photoluminescence spectroscopy illustrated emission bands spanning from the visible (Vis) to near-infrared (NIR) regimes in the deposition pressures range ~ 0–100 mTorr. This is mainly owing to the change in the recombination of electron–hole pairs and charge transfer between the deposited MoS2 films and SiO2 substrate surface under various buffer gas pressures. Additionally, first-principles electronic structure calculations are performed to qualitatively examine the effect of native point-defect species (sulfur-monovacancy and sulfur-divacancy defects) on the electronic structure and optical properties of 2D- MoS2 sheets. It is unveiled that the variation of compositional sulfur-vacancy defect in MoS2 monolayer creates an in–gap defect levels above the valence states, leading to an acceptor character. Importantly, the enhancement in the optical absorption spectra divulged a shift in the optical gap from Vis-NIR window with the increase of sulfur vacancy contents in MoS2 single-layer. The identification of intrinsic point defects may be beneficial for photovoltaic energy conversion at higher wavelengths by designing next generation 2D-semiconductors, which could be of vital significance for growing 2D layers and multilayers into practical technologies

The Impact of Covid-19 Measures on Family Life in the UAE

The aim of the study was to identify the impact on families of the international measures designed to manage the spread of Covid-19, from the viewpoint of families in Al-Ain city, United Arab Emirates. Data were gathered online in semi-structured interviews from 100 families selected by purposive sampling, and results were assessed using the descriptive-analytical method and by referring to the literature. The findings suggest that the international measures on Covid-19, such as remote working, distance learning, and partial lockdown, have had more positive than negative effects on the family. One positive effect is that the international lockdown policies have helped to strengthen both the relationship between couples and the wider family unit. However, such procedures have also had certain negative effects on some families. Considerably more work is required to examine the existence of statistically significant differences between these effects on the family by employing variables such as monthly income and number of family members

Feedback Revisited: Definitional, Structural, and Functional Issues

This article provides a more fundamental overview that addresses the following provisions associated with feedback in an integrative way. First, several linguistic and definitional issues relating to the term ‘feedback’ are discussed. Second, the article draws attention to the challenges and implications associated with online feedback being increasingly used primarily during the contemporary shift toward online learning. Then, the article spots light on the importance of feedback at multiple levels, followed by a discussion of feedback purposes and potential benefits on student learning and progress, both in the short and long term. This article seeks to contribute to the literature on formative feedback by providing a more profound understanding of the conceptualizations of feedback by incorporating definitional, structural, and functional issues about feedback both as a construct and a practice

Postgraduate Students’ Attitudes Towards the Social and Economic Factors Affecting the Emergence of Anomie

This study aimed at identifying the attitudes of postgraduate students in Jordanian universities towards the social factors affecting the emergence of anomie in Jordanian society. The method used was a descriptive analytical approach. The study sample consisted of 273 postgraduate students in five public Jordanian universities enrolled in the second semester of the academic year (2018/ 2019) for the degrees of higher diploma, master’s degree, and doctorate. The study sample was selected using the simple random way. The study used a questionnaire which consisted of (24) items that represent the social dimension affecting the emergence of anomie in Jordanian society. The study results showed that there is a high-impact level for the social factors on the emergence of anomie in Jordanian society from the perspective of postgraduate students in Jordanian universities. The results also revealed that there are statistically significant differences between the mean responses for the study sample individuals towards the social factors affecting the emergence of anomie in Jordanian society due to the variables of monthly income, age, marital status, faculty, religion, job status, while there are no statistically significant differences between the mean responses for the study sample individuals towards the social factors affecting the emergence of anomie in Jordanian society due to the variables of gender and educational qualification. Based on the results, the study concludes with recommendations for further research

Thin-Film LSCs Based on PMMA Nanohybrid Coatings: Device Optimization and Outdoor Performance

This study concerns the design optimization of thin-film luminescent solar concentrators (TLSCs) based on polymethylmethacrylate (PMMA)/silica nanohybrid films doped with coumarin dyestuffs specialized in coloring plastics. Two designs of TLSCs had been prepared and characterized. The first consists of a transparent nanohybrid layer coated on a fluorescent PMMA substrate. The second design is the ordinary configuration in which fluorescent nanohybrid layer is coated on a transparent PMMA substrate. The investigation of the spectral properties and efficiency parameters recommended the best solar energy conversion efficiency for the second design. The outdoor performance of optimized TLSC was also evaluated under clear sky conditions of Riyadh city, and the hourly values of the optical efficiency, ηopt, were calculated for one year. The best performance was achieved in summer since the short circuit current for PV cell was doubled after being attached to TLSC and the value of ηopt reached 40% which is higher than other values recorded before due to the abundant solar energy potential in the Arabian Peninsula

Analysis of Psychological Symptoms Resulting From the COVID-19 Pandemic

The present study aimed to investigate the level of severity of some psychological symptoms resulting from the Coronavirus pandemic, among a sample of Ajman University students in the United Arab Emirates, and to verify the differences between students’ demographic variables. The study used the descriptive-analytical approach and a modified DASS-21 scale, by adding the two scales of phobia and mental distraction to the tool. The reliability of the tool was verified for use on the sample in the current study. The most prominent results indicated that the highest psychological symptoms resulting from the Coronavirus pandemic were phobia (1.53 ± 0.98) with moderate severity, followed by stress (1.44 ± 0.84) with moderate severity, and the lowest was anxiety (1.02 ±0.79) with mild severity. The results also showed that females of the age group (30-40) years and the group less than 30 years of males are the most age categories who developed psychological symptoms. The study recommended the necessity of activating virtual clinical clinics in universities to provide online counseling services to face the psychological repercussions of the Coronavirus pandemic

The Role of Television in Developing Creative and Innovative Ideas Among University Youth: A Field Study on a Sample of University Youth in the United Arab Emirates

University youth. Diagnosing young peoples motives in radio programs and diagnosis. The skills that young people see in their development and standing, and their interconnectedness in television in their marketing, especially since creativity and innovation are among the skills that can be cultivated in individuals, through a stage based on interesting scientific development that inspires creativity and innovation among young people, such as: competitions Scientific programs that stimulate the thinking process and puzzle programs related to the areas related to roads and military status. Developing scientific programs that motivate young people to develop their skills in developing their skills in developing their skills in developing their skills in project development and development programs. That is the essence of this study, which led us to the following results: The field results confirmed that 59% of the sample members believe that Arab programs contribute to marketing and developing creative and innovative skills for Arab youth, compared to 41% who believe in the contribution of foreign programs. Results related to the motives of exposure to programs concluded that 17% are motivated by acquiring new knowledge and scientific experiences, 11% are motivated by learning about the latest discoveries, 41.5% are exposed to learning innovative ways to solve problems, 18% are exposed to entertainment and leisure, and 10.5% are exposed to programs motivated by learning about peoples cultures, and 6% motivated by self- discovery

The Synthesis of NiO/TiO 2

In this work, a heterojunction based on p-type NiO/n-type TiO2 nanostructures has been prepared on the fluorine doped tin oxide (FTO) glass substrate by hydrothermal method. Scanning electron microscopy (SEM) and X-Ray diffraction techniques were used for the morphological and crystalline arrays characterization. The X-ray photoelectron spectroscopy was employed to determine the valence-band offset (VBO) of the NiO/TiO2 heterojunction prepared on FTO glass substrate. The core levels of Ni 2p and Ti 2p were utilized to align the valence-band offset of p-type NiO/n-type TiO2 heterojunction. The valence band offset was found to be ∼0.41 eV and the conduction band was calculated about ∼0.91 eV. The ratio of conduction band offset and the valence-band offset was found to be 2.21