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Diamond films are candidate for a wide range of applications, due to their wide band gap, high thermal conductivity, and chemical stability. In this report, diamond-based heterojunction diodes (HJDs) were fabricated by growing n-type nanocarbon composite in the form of nitrogen-doped ultrananocrystalline diamond/amorphous carbon (UNCD/a-C:H:N) films onto p-type Si substrates. X-ray photoemission and the Fourier transform infrared spectroscopies were employed to examine the contribution of nitrogen atoms from the gas phase into the deposited films. The results indicate the incorporation of nitrogen atoms into the grain boundaries of UNCD/a-C:H film by replacing hydrogen atoms. The capacitance- (C-V-f), conductance- (G/ω-V-f), and series resistance-voltage characteristics of the fabricated Pd/n-(UNCD/a-C:H:N)/p-Si HJDs were studied in the frequency range of 40 kHz-2 MHz. The existence of interface states (Nss) and series resistance (Rs) were attributed to the interruption of the periodic lattice structure at the surface of the fabricated junction as well as the defects on the (UNCD/a-C:H:N)/Si interface. By increasing the frequency (≥500 kHz), the Nss reveals an almost frequency-independent behavior, which indicates that the charges at the interface states cannot follow ac signal at higher frequency. The obtained results demonstrated that the UNCD/a-C:H:N is a promising n-type semiconductor for diamond-based heterostructure diodes.

Diamond is one of the fascinating films appropriate for optoelectronic applications due to its wide bandgap (5.45 eV), high thermal conductivity (3320 W m−1·K−1), and strong chemical stability. In this report, we synthesized a type of diamond film called nanocrystalline diamond (NCD) by employing a physical vapor deposition method. The synthesis process was performed in different ratios of nitrogen and hydrogen mixed gas atmospheres to form nitrogen-doped (n-type) NCD films. A high-resolution scanning electron microscope confirmed the nature of the deposited films to contain diamond nanograins embedded into the amorphous carbon matrix. Sensitive spectroscopic investigations, including X-ray photoemission (XPS) and near-edge X-ray absorption fine structure (NEXAFS), were performed using a synchrotron beam. XPS spectra indicated that the nitrogen content in the film increased with the inflow ratio of nitrogen and hydrogen gas (IN/H). NEXAFS spectra revealed that the σ*C–C peak weakened, accompanied by a π*C=N peak strengthened with nitrogen doping. This structural modification after nitrogen doping was found to generate unpaired electrons with the formation of C–N and C=N bonding in grain boundaries (GBs). The measured electrical conductivity increased with nitrogen content, which confirms the suggestion of structural investigations that nitrogen-doping generated free electrons at the GBs of the NCD films.

We report on the structural evolution of diamond-like carbon (DLC) films by the nanosecond pulsed laser annealing process. DLC film is coated on cemented carbide (WC-Co) by cathodic arc ion plating, which is then annealed by ArF laser (193 nm, 20 ns) at different laser fluences (0.9–1.7 J/cm2). Upon laser annealing, Raman spectra divulge higher sp3 fractions accompanied by a blue shift in the G-peak position, which indicates the changes of sp2 sites from rings to chains. At higher fluence (>1.2 J/cm2), the film converts into reduced graphene oxide confirmed by its Raman-active vibrational modes: D, G, and 2D.

We report the fabrication of p-n+ diamond homojunction through an innovative approach of laser irradiation in liquid-ambient. A shallow phosphorus-doped layer with a high electric conductivity is processed on top of a p-type diamond substrate to form the p-n+ homojunction. The current–voltage measurements at room temperature confirmed high conductivity of the induced n+ layer and showed exceptional rectification properties with an ideality factor of 1.07, excellent low on-resistance of 3.7 × 10−2 Ωcm2, and current density over 260 Acm−2 at forward-biasing of 10 V. Furthermore, undetectable leakage-current provides a rectification ratio exceeding 1010 at ±6 V, promoting the junction in UV detection applications.

We report the fabrication of p-n + diamond homojunction through an innovative approach of laser irradiation in liquid-ambient. A shallow phosphorus-doped layer with a high electric conductivity is processed on top of a p-type diamond substrate to form the p-n + homojunction. The current-voltage measurements at room temperature confirmed high conductivity of the induced n + layer and showed exceptional rectification properties with an ideality factor of 1.07, excellent low on-resistance of 3.7 × 10 −2 Ωcm 2 , and current density over 260 Acm −2 at forward-biasing of 10 V. Furthermore, undetectable leakage-current provides a rectification ratio exceeding 10 10 at ±6 V, promoting the junction in UV detection applications. The process allows further selective and feasible patterned/shallow doping of diamond surfaces beyond the conventional methods, with minimal power consumption and fast production rate, providing more readily electrically contacted devices.

The detrimental effects of the COVID-19 global pandemic have significantly changed the world's view on enacting policies. Egypt has adopted various protocols and measures to control the spread of its causative virus, SARS-CoV-2. This study aims to examine the public trust in decision-makers and help address possible gaps between the sources of information, theoretical guidelines, implementation, and the confidence of youth in response to the pandemic by the main actors involved. An online structured cross-sectional survey was conducted among Egyptian youth during the early COVID-19 pandemic. The questionnaire collected variables, including socio-demographic characteristics, sources of information, and the respondent's confidence in these sources. Out of 406 online respondents, males and females represented, 41.8% and 58.6%, respectively. Ninety-five percent of the respondents received a university or postgraduate education, of which 63.5% were in the medical field, and 82.3% lived in rural areas. Over forty percent reported their source of information was T.V., and 30.3% relied on social media, despite most of the respondents being unconfident in both. In addition, 12.8% and 5.9% reported that their source of information was the Ministry of Health and the WHO, respectively. Over seventy-seven percent of the respondents were concerned with the decisions taken by key actors in the pandemic situation, while 15% were neutral, and 5.4% were not concerned. Infodemics is a substantial public health threat. Public health authorities and governments should take action to ensure comprehensive health information literacy and develop information technology strategies that promote access to evidence-based information.