Effect of post-deposition annealing on the electrical properties of B-Ga2O3 thin films grown on p-Si by plasma-enhanced atomic layer deposition

Cataloged from PDF version of article.Ga2O3 dielectric thin films were deposited on (111)-oriented p-type silicon wafers by plasma-enhanced atomic layer deposition using trimethylgallium and oxygen plasma. Structural analysis of the Ga 2O3 thin films was carried out using grazing-incidence x-ray diffraction. As-deposited films were amorphous. Upon postdeposition annealing at 700, 800, and 900°C for 30min under N2 ambient, films crystallized into β-form monoclinic structure. Electrical properties of the β-Ga2O3 thin films were then investigated by fabricating and characterizing Al/β-Ga2O3/p-Si metal-oxide-semiconductor capacitors. The effect of postdeposition annealing on the leakage current densities, leakage current conduction mechanisms, dielectric constants, flat-band voltages, reverse breakdown voltages, threshold voltages, and effective oxide charges of the capacitors were presented. The effective oxide charges (Qeff) were calculated from the capacitance-voltage (C-V) curves using the flat-band voltage shift and were found as 2.6×1012, 1.9×1012, and 2.5×10 12 cm-2 for samples annealed at 700, 800, and 900°C, respectively. Effective dielectric constants of the films decreased with increasing annealing temperature. This situation was attributed to the formation of an interfacial SiO2 layer during annealing process. Leakage mechanisms in the regions where current increases gradually with voltage were well fitted by the Schottky emission model for films annealed at 700 and 900°C, and by the Frenkel-Poole emission model for film annealed at 800°C. Leakage current density was found to improve with annealing temperature. β-Ga2O3 thin film annealed at 800°C exhibited the highest reverse breakdown field value. © 2014 American Vacuum Society

Electrical characteristics of B-GaN2O3 thin films grown by PEALD

Cataloged from PDF version of article.In this work, 7.5 nm Ga2O3 dielectric thin films have been deposited on p-type (111) silicon wafer using plasma enhanced atomic layer deposition (PEALD) technique. After the deposition, Ga2O3 thin films were annealed under N-2 ambient at 600, 700, and 800 degrees C to obtain beta-phase. The structure and microstructure of the beta-Ga2O3 thin films was carried out by using grazing-incidence X-ray diffraction (GIXRD). To show effect of annealing temperature on the microstructure of beta-Ga2O3 thin films, average crystallite size was obtained from the full width at half maximum (FWHM) of Bragg lines using the Scherrer formula. It was found that crystallite size increased with increasing annealing temperature and changed from 0.8 nm to 9.1 nm with annealing. In order to perform electrical characterization on the deposited films, Al/beta-Ga2O3/p-Si metal-oxide-semiconductor (MOS) type Schottky barrier diodes (SBDs) were fabricated using the beta-Ga2O3 thin films were annealed at 800 degrees C. The main electrical parameters such as leakage current level, reverse breakdown voltage, series resistance (R-S), ideality factor (n), zero-bias barrier height (phi(Bo)), and interface states (N-SS) were obtained from the current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. The RS values were calculated by using Cheung methods. The energy density distribution profile of the interface states as a function of (E-SS-E-V) was obtained from the forward bias I-V measurements by taking bias dependence of ideality factor, effective barrier height (phi(e)), and R-S into account. Also using the Norde function and C-V technique, phi(e) values were calculated and cross-checked. Results show that beta-Ga2O3 thin films deposited by PEALD technique at low temperatures can be used as oxide layer for MOS devices and electrical properties of these devices are influenced by some important parameters such as NSS, RS, and beta-Ga2O3 oxide layer. (C) 2014 Elsevier B.V. All rights reserved

Long-Term Monitoring of Coastal Water Quality Using Sentinel-2 Satellite Images and Google Earth Engine: The Case Study Izmir and Erdek Bays

Coastal waters, crucial for ecology, are threatened by pollution and eutrophication caused by human activities. Monitoring water quality, particularly parameters such as Chlorophyll-a (Chl-a) and Total Suspended Matter (TSM), is essential for sustaining biodiversity and managing aquatic ecosystems. Although in-situ measurement methods are considered reliable, they are expensive, labour-intensive, and spatially limited, which poses challenges for large-scale monitoring. Satellite remote sensing offers an alternative, providing large-scale data for assessing water quality over time. This study utilizes Sentinel-2 Level-1C (Top of Atmosphere reflectance) satellite imagery and the Google Earth Engine (GEE) platform to monitor temporal changes in Izmir and Erdek bays from 2018 to 2024. Indices such as the Normalized Difference Chlorophyll Index (NDCI) and the Normalized Difference Aquatic Vegetation Index (NDAVI) were used for a time series analysis to evaluate water quality, showing high values in both study areas during 2020, particularly in summer, when the correlation was strongest. The Coast 2 Regional CoastColor (C2RCC) algorithm was applied to retrieve Chl-a and TSM values. According to the time series analysis results, Chl-a and TSM parameters were calculated as 7.87 mg/m3 and 2.51 g/m3 and 10.18 mg/m3 and 1.15 g/m3 respectively for Izmir and Erdek bays. Results also show a correlation between the indices and water quality parameters. This suggests that satellite-based methods effectively monitor complex aquatic ecosystems without in-situ measurements. In order to increase accuracy and reliability, future work involves integrating advanced modelling techniques, such as deep learning networks, with remote sensing data into the GEE cloud-based platform

Effect of Film Thickness on the Electrical Properties of AlN Films Prepared by Plasma-Enhanced Atomic Layer Deposition

In this paper, AlN thin films with two different thicknesses, i.e., 7 and 47 nm, were deposited at 200 °C on p-type Si substrates by plasma-enhanced atomic layer deposition using trimethylaluminum and ammonia. To investigate the electrical characteristics of these AlN films, MIS capacitor structures were fabricated and characterized using current-voltage and high-frequency (1 MHz) capacitance-voltage measurements. The results showed that the current transport mechanism under accumulation mode is strongly dependent on the applied electric field and thickness of the AlN film. Possible conduction mechanisms were analyzed, and the basic electrical parameters were extracted and compared for AlN thin films with different thicknesses. Compared with 7-nm-thick film, a 47-nm-thick AlN film showed a lower effective charge density and threshold voltage along with a higher dielectric constant. © 2015 IEEE

Current transport mechanisms in plasma-enhanced atomic layer deposited AlN thin films

Here, we report on the current transport mechanisms in AlN thin films deposited at a low temperature (i.e., 200°C) on p-type Si substrates by plasma-enhanced atomic layer deposition. Structural characterization of the deposited AlN was carried out using grazing-incidence X-ray diffraction, revealing polycrystalline films with a wurtzite (hexagonal) structure. Al/AlN/ p-Si metal-insulator-semiconductor (MIS) capacitor structures were fabricated and investigated under negative bias by performing current-voltage measurements. As a function of the applied electric field, different types of current transport mechanisms were observed; i.e., ohmic conduction (15.2-21.5 MV/m), Schottky emission (23.6-39.5 MV/m), Frenkel-Poole emission (63.8-211.8 MV/m), trap-assisted tunneling (226-280 MV/m), and Fowler-Nordheim tunneling (290-447 MV/m). Electrical properties of the insulating AlN layer and the fabricated Al/AlN/p-Si MIS capacitor structure such as dielectric constant, flat-band voltage, effective charge density, and threshold voltage were also determined from the capacitance-voltage measurements. © 2015 AIP Publishing LLC

3 years of liraglutide versus placebo for type 2 diabetes risk reduction and weight management in individuals with prediabetes: a randomised, double-blind trial

Background Liraglutide 3\ub70 mg was shown to reduce bodyweight and improve glucose metabolism after the 56-week period of this trial, one of four trials in the SCALE programme. In the 3-year assessment of the SCALE Obesity and Prediabetes trial we aimed to evaluate the proportion of individuals with prediabetes who were diagnosed with type 2 diabetes. Methods In this randomised, double-blind, placebo-controlled trial, adults with prediabetes and a body-mass index of at least 30 kg/m2, or at least 27 kg/m2 with comorbidities, were randomised 2:1, using a telephone or web-based system, to once-daily subcutaneous liraglutide 3\ub70 mg or matched placebo, as an adjunct to a reduced-calorie diet and increased physical activity. Time to diabetes onset by 160 weeks was the primary outcome, evaluated in all randomised treated individuals with at least one post-baseline assessment. The trial was conducted at 191 clinical research sites in 27 countries and is registered with ClinicalTrials.gov, number NCT01272219. Findings The study ran between June 1, 2011, and March 2, 2015. We randomly assigned 2254 patients to receive liraglutide (n=1505) or placebo (n=749). 1128 (50%) participants completed the study up to week 160, after withdrawal of 714 (47%) participants in the liraglutide group and 412 (55%) participants in the placebo group. By week 160, 26 (2%) of 1472 individuals in the liraglutide group versus 46 (6%) of 738 in the placebo group were diagnosed with diabetes while on treatment. The mean time from randomisation to diagnosis was 99 (SD 47) weeks for the 26 individuals in the liraglutide group versus 87 (47) weeks for the 46 individuals in the placebo group. Taking the different diagnosis frequencies between the treatment groups into account, the time to onset of diabetes over 160 weeks among all randomised individuals was 2\ub77 times longer with liraglutide than with placebo (95% CI 1\ub79 to 3\ub79, p<0\ub70001), corresponding with a hazard ratio of 0\ub721 (95% CI 0\ub713\u20130\ub734). Liraglutide induced greater weight loss than placebo at week 160 (\u20136\ub71 [SD 7\ub73] vs 121\ub79% [6\ub73]; estimated treatment difference 124\ub73%, 95% CI 124\ub79 to 123\ub77, p<0\ub70001). Serious adverse events were reported by 227 (15%) of 1501 randomised treated individuals in the liraglutide group versus 96 (13%) of 747 individuals in the placebo group. Interpretation In this trial, we provide results for 3 years of treatment, with the limitation that withdrawn individuals were not followed up after discontinuation. Liraglutide 3\ub70 mg might provide health benefits in terms of reduced risk of diabetes in individuals with obesity and prediabetes. Funding Novo Nordisk, Denmark

Apium plants: Beyond simple food and phytopharmacological applications

Apium plants belong to the Apiaceae family and are included among plants that have been in use in traditional medicine for thousands of years worldwide, including in the Mediterranean, as well as the tropical and subtropical regions of Asia and Africa. Some highlighted medical benefits include prevention of coronary and vascular diseases. Their phytochemical constituents consist of bergapten, flavonoids, glycosides, furanocoumarins, furocoumarin, limonene, psoralen, xanthotoxin, and selinene. Some of their pharmacological properties include anticancer, antioxidant, antimicrobial, antifungal, nematocidal, anti-rheumatism, antiasthma, anti-bronchitis, hepatoprotective, appetizer, anticonvulsant, antispasmodic, breast milk inducer, anti-jaundice, antihypertensive, anti-dysmenorrhea, prevention of cardiovascular diseases, and spermatogenesis induction. The present review summarizes data on ecology, botany, cultivation, habitat, medicinal use, phytochemical composition, preclinical and clinical pharmacological efficacy of Apium plants and provides future direction on how to take full advantage of Apium plants for the optimal benefit to mankind.N. Martins would like to thank the Portuguese Foundation for Science and Technology (FCT-Portugal) for the strategic project ref. UID/BIM/04293/2013 and “NORTE2020-Northern Regional Operational Program” (NORTE-01-0145-FEDER-000012)

Kocuria kristinae infection associated with acute cholecystitis

BACKGROUND: Kocuria, previously classified into the genus of Micrococcus, is commonly found on human skin. Two species, K. rosea and K. kristinae, are etiologically associated with catheter-related bacteremia. CASE PRESENTATION: We describe the first case of K. kristinae infection associated with acute cholecystitis. The microorganism was isolated from the bile of a 56-year old Chinese man who underwent laparoscopic cholecystectomy. He developed post-operative fever that resolved readily after levofloxacin treatment. CONCLUSION: Our report of K. kristinae infection associated with acute cholecystitis expands the clinical spectrum of infections caused by this group of bacteria. With increasing number of recent reports describing the association between Kocuria spp. and infectious diseases, the significance of their isolation from clinical specimens cannot be underestimated. A complete picture of infections related to Kocuria spp. will have to await the documentation of more clinical cases

Oxidative stress biomarkers and acetylcholinesterase activity in human erythrocytes exposed to clomazone (in vitro)

The aim of this study was to investigate the effect of clomazone herbicide on oxidative stress biomarkers and acetylcholinesterase activity in human erythrocytes in in vitro conditions. The activity of catalase (CAT), superoxide dismutase (SOD) and acetylcholinesterase (AChE), as well as the levels of thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) were measured in human erythrocytes exposed (in vitro) to clomazone at varying concentrations in the range of 0, 100, 250 and 500 µg/L for 1 h at 37 °C.TBARS levels were significantly higher in erythrocytes incubated with clomazone at 100, 250 and 500 µg/L. However, erythrocyte CAT and AChE activities were decreased at all concentrations tested. SOD activity was increased only at 100 µg/L of clomazone. GSH levels did not change with clomazone exposure. These results clearly showed clomazone to induce oxidative stress and AChE inhibition in human erythrocytes (in vitro). We, thus, suggest a possible role of ROS on toxicity mechanism induced by clomazone in humans

Decreased glutathione levels and impaired antioxidant enzyme activities in drug-naive first-episode schizophrenic patients

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to determine glutathione levels and antioxidant enzyme activities in the drug-naive first-episode patients with schizophrenia in comparison with healthy control subjects.</p> <p>Methods</p> <p>It was a case-controlled study carried on twenty-three patients (20 men and 3 women, mean age = 29.3 ± 7.5 years) recruited in their first-episode of schizophrenia and 40 healthy control subjects (36 men and 9 women, mean age = 29.6 ± 6.2 years). In patients, the blood samples were obtained prior to the initiation of neuroleptic treatments. Glutathione levels: total glutathione (GSHt), reduced glutathione (GSHr) and oxidized glutathione (GSSG) and antioxidant enzyme activities: superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) were determined by spectrophotometry.</p> <p>Results</p> <p>GSHt and reduced GSHr were significantly lower in patients than in controls, whereas GSSG was significantly higher in patients. GPx activity was significantly higher in patients compared to control subjects. CAT activity was significantly lower in patients, whereas the SOD activity was comparable to that of controls.</p> <p>Conclusion</p> <p>This is a report of decreased plasma levels of GSHt and GSHr, and impaired antioxidant enzyme activities in drug-naive first-episode patients with schizophrenia. The GSH deficit seems to be implicated in psychosis, and may be an important indirect biomarker of oxidative stress in schizophrenia early in the course of illness. Finally, our results provide support for further studies of the possible role of antioxidants as neuroprotective therapeutic strategies for schizophrenia from early stages.</p