The article presents a systematic study of Sb-doped Zn1−xMgxO layers, with various concentrations of Mg, that were successfully grown by plasma-assisted MBE on polar a- and c-oriented and non-polar ...r-oriented sapphire substrates. X-ray diffraction confirmed the polar c-orientation of alloys grown on c-and a-oriented sapphire and non-polar structures grown on r-oriented substrates. A uniform depth distribution of the Sb dopant at level of 2 × 1020 cm−3 was determined by SIMS measurements. Raman spectroscopy revealed the presence of Sb-related modes in all samples. It also showed that Mg alloying reduces the compressive strain associated with Sb doping in ZnO. XPS analysis indicates that the chemical state of Sb atoms in ZnMgO is 3+, suggesting a substitutional position of SbZn, probably associated with two VZn vacancies. Luminescence and transmission spectra were measured to determine the band gaps of the Zn1−xMgxO layers. The band gap energies extracted from the transmittance measurements differ slightly for the a, c, and r substrate orientations, and the differences increase with increasing Mg content, despite identical growth conditions. The differences between the energy gaps, determined from transmission and PL peaks, are closely correlated with the Stokes shift and increase with the Mg content in the analyzed series of ZnMgO layers.
The article presents a systematic study of Sb-doped Zn
Mg
O layers, with various concentrations of Mg, that were successfully grown by plasma-assisted MBE on polar
- and
-oriented and non-polar
...-oriented sapphire substrates. X-ray diffraction confirmed the polar
-orientation of alloys grown on
-and
-oriented sapphire and non-polar structures grown on
-oriented substrates. A uniform depth distribution of the Sb dopant at level of 2 × 10
cm
was determined by SIMS measurements. Raman spectroscopy revealed the presence of Sb-related modes in all samples. It also showed that Mg alloying reduces the compressive strain associated with Sb doping in ZnO. XPS analysis indicates that the chemical state of Sb atoms in ZnMgO is 3+, suggesting a substitutional position of Sb
, probably associated with two V
vacancies. Luminescence and transmission spectra were measured to determine the band gaps of the Zn
Mg
O layers. The band gap energies extracted from the transmittance measurements differ slightly for the
,
, and
substrate orientations, and the differences increase with increasing Mg content, despite identical growth conditions. The differences between the energy gaps, determined from transmission and PL peaks, are closely correlated with the Stokes shift and increase with the Mg content in the analyzed series of ZnMgO layers.
The article presents a systematic study of Sb-doped Znsub.1−xMgsub.xO layers, with various concentrations of Mg, that were successfully grown by plasma-assisted MBE on polar a- and c-oriented and ...non-polar r-oriented sapphire substrates. X-ray diffraction confirmed the polar c-orientation of alloys grown on c-and a-oriented sapphire and non-polar structures grown on r-oriented substrates. A uniform depth distribution of the Sb dopant at level of 2 × 10sup.20 cmsup.−3 was determined by SIMS measurements. Raman spectroscopy revealed the presence of Sb-related modes in all samples. It also showed that Mg alloying reduces the compressive strain associated with Sb doping in ZnO. XPS analysis indicates that the chemical state of Sb atoms in ZnMgO is 3+, suggesting a substitutional position of Sbsub.Zn, probably associated with two Vsub.Zn vacancies. Luminescence and transmission spectra were measured to determine the band gaps of the Znsub.1−xMgsub.xO layers. The band gap energies extracted from the transmittance measurements differ slightly for the a, c, and r substrate orientations, and the differences increase with increasing Mg content, despite identical growth conditions. The differences between the energy gaps, determined from transmission and PL peaks, are closely correlated with the Stokes shift and increase with the Mg content in the analyzed series of ZnMgO layers.
Research indicates that mental health worsened during the Coronavirus crisis, in particular among women and university students. However, few longitudinal studies have so far investigated the changes ...in mental health outcomes across three subsequent waves of the COVID-19 pandemic. Therefore, this study aims to examine changes in mental health among university students.
A total of 1,961university students from Poland, at mean age 23.23 years (SD = 3.16, 57.47% of women) were included in this repeated cross-sectional study across three waves of the COVID-19 pandemic: W1 (n = 657), W2 (n = 654), and W3 (n = 650). They completed the online survey with the Generalized Anxiety Disorder (GAD-7), Perceived Stress Scale (PSS-10), General Self-Rated Health (GSRH), and Satisfaction with Life Scale (SWLS), as well as sociodemographic variables.
The prevalence of people at high risk of anxiety and perceived stress, poorer physical health, and low life satisfaction changed significantly across three waves of the COVID-19 pandemic. The results of the two-way ANOVA showed that both the wave (W1<W2<W3) and gender (men<women) had a significant impact on the level of anxiety. Statistically significant changes in perceived stress were found between pandemic waves (W1>W2, W1>W3), and genders (men<women). Self-reported physical health significantly deteriorated in W3 compared to W1 and W2 (W1>W3, W2>W3), and was significantly worse in women than in men. The level of life satisfaction also decreased significantly in W3 (W1>W3, W2>W3), but did not differ between men and women. High GAD risk was presented two times more frequently among women and people who subjectively assessed their health as poor, three times more likely in participants dissatisfied with their lives, and seven times more probably in persons with high-stress levels.
The results of this study consistently indicate (using parametric and non-parametric statistical analysis) that there are significant differences in mental health problems across three waves of the COVID-19 pandemic. It suggests that pandemic waves should be considered in future review studies and meta-analyses. Furthermore, these findings indicate a potential role for prevention and intervention programs aimed at alleviating life satisfaction and subjective assessment of health and improving coping skills to reduce stress and anxiety.
Although numerous studies investigated the predictors of vaccination intention and decision, little is known about the relationship between vaccination and well-being. This study compares the ...physical and mental health dimensions among vaccinated and unvaccinated people. In a cross-sectional online survey, 706 university students from Poland (mean age of 23 years, 76% of women) participated in this study during the fourth pandemic wave (November–December 2021). Standardized questionnaires with a Likert response scale were included in the survey to measure spirituality, exposure to the COVID-19 pandemic, perceived physical health, stress, coronavirus-related PTSD, fear of COVID-19, anxiety, depression, and life satisfaction. Consistent with the fuzzy-trace theory, the unvaccinated sample was younger and scored significantly lower than the vaccinated group in exposure to COVID-19, perceived physical health, stress, coronavirus-related PTSD, fear of COVID-19, and depression, while higher in life satisfaction. The network analysis showed that mental health plays a crucial role in both groups, with the central influence of anxiety and stress on depression and life satisfaction. The message on vaccination to university students should focus on the benefits of vaccination in maintaining the status quo of good health and well-being. Campus prevention programs should primarily aim to reduce anxiety, stress, and negative emotions by teaching students coping strategies, relaxation techniques, and mindfulness.
PDF
