Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Cureus ; 16(6): e63073, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38933342

RESUMEN

Background Gastroesophageal reflux disease (GERD) is a global gastrointestinal disorder, and obesity is a particular risk factor. Symptoms of GERD, such as heartburn and acid reflux, are caused by abnormal relaxation in the lower esophagus, causing gastric acid reflux. Persistent symptoms can affect the patient's quality of life (QOL) and can cause complications, such as esophageal adenocarcinoma. Management of GERD includes lifestyle changes, antacids, and anti-reflux surgery. Even though GERD is a common disease, few research has been carried out on it in Saudi Arabia. Aim This study aimed to estimate the prevalence of GERD and its associated risk factors among obese individuals in the Al-Baha region population and the effect of GERD on their QOL. Methods A cross-sectional study included 314 obese participants from the Al-Baha region. A questionnaire was filled out to measure the prevalence of GERD, risk factors, and effects on the QOL of the participants. Data were analyzed by the IBM SPSS Statistics for Windows, version 26.0 (released 2019, IBM Corp., Armonk, NY). Descriptive statistics and the chi-squared test were applied. Logistic regression analysis was used to determine the factors associated with the incidence of GERD. A p-value of <0.05 was considered statistically significant. Results A total of 314 patients who met our inclusion criteria completed the survey; 42% of them were women, the mean age of all patients was 35.3 ± 12.9 years, and 38.2% of the patients were diagnosed with GERD. Epigastric pain and burning sensation were the most common symptoms (44.9%). Five out of six domains in the QOL questionnaire showed more effects among GERD participants than non-GERD participants, and the results were statistically significant (p = 0.001). Logistic regression analysis showed that men are 1.8 times more likely than women to be diagnosed with GERD, and smokers have 2.6 times the risk of being diagnosed with GERD than non-smokers. Conclusion The present study showed a high prevalence of GERD among obese patients in the Al-Baha region, negatively affecting their QOL. Major risk factors included gender, smoking, dyslipidemia, and hypertension. Public health programs to raise awareness of these risk factors and lifestyle habits are necessary to improve QOL and prevent complications.

2.
Cureus ; 16(3): e56233, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38618411

RESUMEN

Background and objective Bimatoprost ophthalmic solution (0.03%) is used for the treatment of ocular hypertension. However, one of the side effects of this prescription is that it causes overgrowth of eyelashes, causing hypertrichosis. Therefore, the Bimatoprost ophthalmic solution was rebranded to be used for cosmetic purposes. This study aims to assess the awareness and practices of female university students regarding the use of Careprost (Bimatoprost, Latisse, Allergan, Inc., Irvine, CA) for cosmetic purposes. Methodology A descriptive cross-sectional study was conducted among female students at Bisha University, including those from medical and non-medical colleges, spanning from November 2022 to February 2023. All participants who completed the study questionnaire were considered for analysis, but those who had missing answers were excluded from the study. The total number of participants was 305, representing an 81.2% response rate out of the 376 surveys distributed. Results A total of 305 students completed the survey, with approximately 132 (54.5%) from the medical college and 173 (65.3%) from the non-medical college. Approximately 32 (24.2%) of participants from the medical college and 51 (29.4%) from the non-medical college understood that Bimatoprost drops can be used for the elongation of eyelashes. More than half of the participants were not aware of the side effects of Careprost (0.03%), including 65 (49.2%) medical students and 108 (62.7%) non-medical students. In total, 42 (13.77%) of the participants believed that Careprost (0.03%) could be administered without a prescription. Among the participants, 75 (24.59%) reported that they had previously used Careprost (0.03%) eye drops. Additionally, more than one-fourth of the participants (83, 27.2%) thought that Careprost (0.03%) could be used for eyelash elongation. Conclusions This study revealed that female university students had a poor level of awareness and practices about the cosmetic uses of Careprost (0.03%) eye drops for eyelashes. A better awareness level was noted regarding the side effects of Careprost drops, which may have contributed to a low utilization rate among female students.

3.
Radiat Prot Dosimetry ; 200(7): 687-692, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38678363

RESUMEN

The objective of this study was to evaluate patient knowledge and understanding of ionising radiation and dosage, as well as the accompanying risks related to computed tomography scans. A total of 412 outpatients who underwent computed tomography (CT) scans were surveyed to assess their understanding of radiation dose and exposure risks. CT was correctly classified as an ionising radiation by 56.8% of the respondents. More than half of the patients reported that a CT scan increases the probability of inducing cancer. Awareness of varying radiation doses in different CT exams was noted in 75.2% of patients, but only 21.4% reported having discussions with their physician about radiation dose. Gender, age and employment were significantly correlated with knowledge levels. The survey findings indicate a limited understanding of the hazards associated with ionising radiation used in CT scans, highlighting a need for increased awareness and education on radiation protection to ensure informed consent.


Asunto(s)
Conocimientos, Actitudes y Práctica en Salud , Dosis de Radiación , Exposición a la Radiación , Radiación Ionizante , Tomografía Computarizada por Rayos X , Humanos , Arabia Saudita , Masculino , Tomografía Computarizada por Rayos X/métodos , Femenino , Persona de Mediana Edad , Adulto , Exposición a la Radiación/análisis , Encuestas y Cuestionarios , Anciano , Adulto Joven , Protección Radiológica , Adolescente
4.
Healthcare (Basel) ; 11(18)2023 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-37761705

RESUMEN

BACKGROUND: The lack of local guidelines and regulations for the administration of anesthesia in magnetic resonance imaging (MRI) units presents a potential risk to patient safety in Saudi Arabia. Hence, this study aimed to evaluate the extent to which hospitals in Saudi Arabia follow international guidelines and recommendations for the safe and effective administration of anesthesia in an MRI environment. METHODS: This study used a questionnaire that was distributed to 31 medical facilities in Saudi Arabia that provided anesthesia in MRI units. RESULTS: The findings of the study revealed that the mean compliance with the 17 guidelines across the 31 sites was 77%; 5 of the 31 sites (16.1%) had a compliance rate of less than 50% with the recommended guidelines. Only 19.4% of the institutes provided general safety education. Communication breakdowns between anesthesia providers and MRI teams were reported. CONCLUSIONS: To conclude, this survey highlights the status of anesthesia standards in Saudi Arabian MRI units and emphasizes areas that require better adherence to international guidelines. The results call for targeted interventions, including the formulation of specific national anesthesia guidelines for MRI settings. Communication breakdowns between anesthesia providers and MRI teams were reported at a rate of 83.9% during the administration of a gadolinium contrast agent. There were additional breakdowns, particularly for high-risk patients with implants, such as impaired respirators (74.2%), thus requiring further investigation due to potential safety incidents during MRI procedures. While considering the limitations of this study, such as potential biases and the low response rate, it provides a valuable foundation for refining protocols and promoting standardized practices in Saudi Arabian healthcare.

5.
Molecules ; 28(14)2023 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-37513185

RESUMEN

To address the high tolerance of biofilms to antibiotics, it is urgent to develop new strategies to fight against these bacterial consortia. An innovative antibiofilm nanovector drug delivery system, consisting of Dispersin B-permethylated-ß-cyclodextrin/ciprofloxacin adamantyl (DspB-ß-CD/CIP-Ad), is described here. For this purpose, complexation assays between CIP-Ad and (i) unmodified ß-CD and (ii) different derivatives of ß-CD, which are 2,3-O-dimethyl-ß-CD, 2,6-O-dimethyl-ß-CD, and 2,3,6-O-trimethyl-ß-CD, were tested. A stoichiometry of 1/1 was obtained for the ß-CD/CIP-Ad complex by NMR analysis. Isothermal Titration Calorimetry (ITC) experiments were carried out to determine Ka, ΔH, and ΔS thermodynamic parameters of the complex between ß-CD and its different derivatives in the presence of CIP-Ad. A stoichiometry of 1/1 for ß-CD/CIP-Ad complexes was confirmed with variable affinity according to the type of methylation. A phase solubility study showed increased CIP-Ad solubility with CD concentration, pointing out complex formation. The evaluation of the antibacterial activity of CIP-Ad and the 2,3-O-dimethyl-ß-CD/CIP-Ad or 2,3,6-O-trimethyl-ß-CD/CIP-Ad complexes was performed on Staphylococcus epidermidis (S. epidermidis) strains. The Minimum Inhibitory Concentration (MIC) studies showed that the complex of CIP-Ad and 2,3-O-dimethyl-ß-CD exhibited a similar antimicrobial activity to CIP-Ad alone, while the interaction with 2,3,6-O-trimethyl-ß-CD increased MIC values. Antimicrobial assays on S. epidermidis biofilms demonstrated that the synergistic effect observed with the DspB/CIP association was partly maintained with the 2,3-O-dimethyl-ß-CDs/CIP-Ad complex. To obtain this "all-in-one" drug delivery system, able to destroy the biofilm matrix and release the antibiotic simultaneously, we covalently grafted DspB on three carboxylic permethylated CD derivatives with different-length spacer arms. The strategy was validated by demonstrating that a DspB-permethylated-ß-CD/ciprofloxacin-Ad system exhibited efficient antibiofilm activity.


Asunto(s)
Ciclodextrinas , Ciclodextrinas/química , Ciprofloxacina/farmacología , Ciprofloxacina/química , Antibacterianos/farmacología , Antibacterianos/química , Termodinámica , Staphylococcus epidermidis
6.
Cureus ; 15(5): e38493, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37273372

RESUMEN

Gadolinium-based contrast agents (GBCAs) are commonly used in magnetic resonance imaging (MRI) to enhance the visualisation and characterisation of the region of interest/lesion. Internal structures are well seen with MRI with good spatial resolution. Although MRI is generally considered safe during pregnancy, concerns have been raised regarding the safety of GBCAs, particularly during the first trimester. Limited studies have been conducted to assess the safety of GBCAs in pregnant women, with conflicting results. A comprehensive literature search was conducted using PubMed, SpringerLink, Medscape, ResearchGate and Wiley Online Library. The search terms included various combinations of MRI, pregnancy, first trimester, gadolinium contrast agents, foetus, risk, and toxicity. The search criteria were articles published in English in the last 20 years and indexed in the MEDLINE or Embase databases. The majority of studies found no definitive evidence that GBCAs are harmful during pregnancy, particularly during the first trimester. Some studies reported no increased risk of adverse outcomes in infants exposed to GBCAs during the first trimester. However, other studies showed inconsistent results. Retrospective cohort studies provided some reassurance regarding the safety of GBCAs when indicated in pregnant women but did not address potential long-term adverse outcomes in infants exposed to GBCAs during gestation. The literature review also highlights the importance of further evaluating the subacute and chronic effects of GBCA exposure in infants. The safety of GBCAs during pregnancy, particularly during the first trimester, remains uncertain. More large-scale, long-term studies are needed to clarify the safety of GBCAs in pregnant women and their potential effects on foetal and neonatal outcomes. Until conclusive evidence is available, healthcare providers should carefully weigh the benefits and risks of using GBCAs during pregnancy and consider alternative imaging modalities, such as non-contrast MRI or ultrasound, when necessary.

7.
Cureus ; 15(4): e37698, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37081900

RESUMEN

Magnetic resonance imaging (MRI) played a significant role in the digital health platforms that influenced and supported modern medicine. However, there is a shortage of MRI in low- and middle-income countries (LMICs). The International Society of Radiology offers a detailed plan for LMICs to advance imaging quality in the global health agenda. The overarching objective of this scoping review was to determine the impact of MRI in healthcare in LMICs. This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify available evidence. We systematically searched four academic databases for peer-reviewed literature published between 2018 and 2021, namely, Medline, PubMed, Web of Science, and Scopus, as well as Google Scholar as a source for gray literature. The search identified 54 articles. We identified a range of reasons for introducing MRI in LMICs. Nonetheless, some challenges to accepting MRI as a method of healthcare have been reported, including technological, regulatory, and economical challenges. To implement the proposed plan, the involvement of professional and international organizations is considered crucial. The establishment of an International Commission on Medical Imaging under the umbrella of international organizations is suggested and collaboration with other diagnostic disciplines is encouraged to raise awareness of the importance of upscale diagnostics at large and to foster its integration into the care pathway globally.

8.
Healthcare (Basel) ; 11(5)2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36900726

RESUMEN

PURPOSE: The American College of Radiology (ACR) requires MR personnel not to work alone due to the increased risk of safety issues such as projectiles, aggressive patients, and technologist fatigue. As a result, we intend to assess the current safety of lone-working MRI technologists in MRI departments in Saudi Arabia. MATERIALS AND METHODS: A cross-sectional study using a self-report questionnaire was conducted in 88 Saudi hospitals. RESULTS: A response rate of 64% (174/270) was obtained among the 270 MRI technologists which were identified. The study discovered that 86% of MRI technologists had prior experience working alone. In terms of MRI safety training, 63% of MRI technologists received such training. A question about lone MRI workers' awareness of the ACR's recommendations revealed that 38% were unaware of such recommendations. Furthermore, 22% were misinformed, believing that working alone in an MRI unit is optional or depends on the individual's desire to work alone. Working alone has the primary consequence of being statistically significantly associated with projectile/object-related accidents/mistakes (p = 0.03). CONCLUSION: Saudi Arabian MRI technologists have extensive experience working alone without supervision. Most MRI technologists are unaware of lone working regulations, which has raised concerns about accidents/mistakes. There is a need for MRI safety training and adequate practical experience to raise awareness of MRI safety regulations and policies related to lone working among departments and MRI workers.

9.
Risk Manag Healthc Policy ; 16: 199-208, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36798619

RESUMEN

Aim: The aim of this study is to investigate the safety practices used by MRI departments in Saudi Arabia. Methods: A cross-sectional study across 113 private and public hospitals was conducted in Saudi Arabia. A survey questionnaire was designed and sent to 113 MRI units. The questionnaire consisted of 43 items under 14 sections for the assessment of MRI safety practices. These 14 sections are related to (i) MRI and its safety, (ii) MRI usage and its safety, and (iii) safety of the MRI technologists and reporting of adverse effects during the usage. The American College of Radiology (ACR) guidance document on MRI safety practices was used as a template for this survey. Data were analyzed using IBM SPSS Statistical software for Windows version 26.0 (IBM Corp., Armonk, NY, USA). Results: Of the 43 items assessed, only 3 items' binary responses (Yes & No) did not differ much. A greater proportion of positive responses for 40 items (93%) regarding MRI safety practices. More than 50% of the participants claimed that their departments lacked a Magnetic Resonance Safety Officer (MRSO). Regarding regular safety training programs, less than 50% received training in MRI safety. Handheld metal detectors were found in only 39% of the MRI units. Conclusion: The majority of MRI units in Saudi Arabia have demonstrated compliance with majority of ACR MRI safety recommendations; nonetheless, there are two main items for which the guidelines may not be attained: MRSO and regular MRI safety training programs. By taking into account the limitations of this study, it is strongly recommended to assign MRSO and implement annual MRI safety training to improve MRI safety practices for both patients and healthcare workers.

10.
Appl Opt ; 61(20): 5885-5893, 2022 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-36255827

RESUMEN

Due to tremendous design flexibility and ease of light control capability, the photonic crystal fiber offers efficient, flexible, and miniaturized plasmonic biosensors with attractive features. In this work, a high index (GeO2 doped silica) core flat fiber is proposed and analyzed for RI sensing ranging from 1.53 to 1.60. A rectangular analyte channel is created on top of a flat fiber to better handle the liquid analyte. To introduce the plasmonic effect, TiO2 and gold are deposited to the analyte channel. The sensing performance is carried out for two operating wavelengths, as two peaks are obtained for each analyte. The second operating wavelength shows better sensing performance than the first one. However, the proposed sensor offers average wavelength sensitivity of 5000 nm/RIU with a sensor resolution of 2×10-05 RIU. In addition, the proposed sensor shows identical linearity, which is quite rare in prior sensors. Moreover, the proposed flat sensor provides outstanding detection accuracy of 0.01nm-1, detection limit of 79.28 nm, signal to noise ratio of -4.1497dB, and figure of merit of 50RIU-1. Owing to outstanding sensing performance and a unique detection range, this sensor can be effectively used in biological and organic analyte sensing applications.


Asunto(s)
Óptica y Fotónica , Resonancia por Plasmón de Superficie , Diseño de Equipo , Oro/química , Dióxido de Silicio
11.
Int J Gen Med ; 15: 6289-6299, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35924179

RESUMEN

Purpose: Magnetic resonance imaging (MRI) is an important diagnostic method in modern clinical medicine. Patients' knowledge about MRI is of utmost importance for optimizing the workflow, safety, and patient comfort and saving valuable time for the MRI department. This study investigates patient knowledge levels regarding MRI safety before an MRI examination. Patients and Methods: A cross-sectional survey was completed by 200 patients who required MRI. Recruitment occurred over eight weeks in governmental and private hospitals in Saudi Arabia; both hospitals and participants were selected randomly. The questionnaire was given to the patients prior to their MRI scans. Descriptive statistics and chi-square tests were performed to identify relationships between knowledge of MRI safety and selected demographic groupings (age, gender, education level, income level). It also evaluates their source of information and assesses the patient's previous experience regarding MRI scans. . Results: The study sample consisted of 200 patients from 230 surveys distributed in Saudi Arabia, and the response rate was ~ 87%. Depending on the P-values of the chi-square statistical test to find the relationship between socio-demographic factors and patient' knowledge level, the results showed a significant association (p-value=0.006) between age and gender and the level of knowledge relating to MRI safety issues. A similar significance (p-value=0.042) is observed between the knowledge level of patients and their educational level and annual income. In addition, a highly significant association (p-value<0.001) is found between education level or previous experience and whether people seek information about MRI safety. Conclusion: The study findings suggest that a complex combination of factors affects patient knowledge regarding MRI safety before an MRI examination. Hence, the hospital and radiological department must provide the patient with accurate information about MRI. .

12.
Acta Radiol Open ; 11(6): 20584601221105228, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35677731

RESUMEN

Background: Magnetic Resonance Imaging (MRI) is considered a vital in depicting multiple sclerosis (MS) lesions. Current studies demonstrate that proton density (PD) weighted images (WI) are superior to T2 WI in detecting MS lesions (plaques) in the spinal cord. Purpose: To evaluate the diagnostic value of filtered fused PD/T2 weighted images in detecting cervical spinal cord MS lesions. Material and Methods: In this retrospective study, we selected a sample size of 50 MS patients. Using contrast limited adaptive histogram equalization (CLAHE), a digital image processing filter was used on the (PD/T2) fused images. The produced images were inspected and compared to the original PD images by two experienced neuroradiologists using interobserver and intraobserver. An ROI analysis was also performed on the processed and original PD images. Results: The repeatability measurement of the match between the two examinations was highly consistent for both neuroradiologists. The repeatability for both neuroradiologists was 96.05%, and the error measurement was 3.95%. The reproducibility measurement of the neuroradiologist's evaluation shows that the processed images could help to identify lesions better [excellent (84.87%)] than PD images [good (61.19%)]. ROIs analysis was performed on 113 MS lesions and normal areas in different images within the sample size. It revealed an enhanced ratio of 2.2 between MS lesions and normal spinal cord tissue in processed fused images compared to 1.34 in PD images. Conclusion: The processed images of the fused images (PD/T2) have superior diagnostic sensitivity for MS lesions in the cervical spine than PD images alone.

13.
Radiat Prot Dosimetry ; 194(2-3): 163-168, 2021 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-34164690

RESUMEN

This study aimed to estimate a baseline for the effective doses received by radiography internship students in Saudi Arabia. A retrospective study was conducted from 2015 to 2018 to discern the effective dose measurements for a total of 206 students using optically stimulated luminescence dosemeters. Readings were performed using the OSLR-250 Automatic Reader. Data analysis was carried out on 813 readouts. The annual mean effective dose averaged over a period of 4 y was found to be 0.55 mSv, with a standard deviation of 0.34 mSv and a range of 0.14-1.58 mSv. The results show that 92% ($\frac{190}{206}$) of the students received annual effective doses of <1 mSv. No annual dose record exceeded the limits recommended by authorities (20 mSv/y). The study concluded that the applied radiation protection measures along with education and training help create a safe work environment for radiography internship students.


Asunto(s)
Internado y Residencia , Exposición Profesional , Dosimetría con Luminiscencia Ópticamente Estimulada , Humanos , Exposición Profesional/análisis , Dosis de Radiación , Radiografía , Estudios Retrospectivos , Arabia Saudita , Estudiantes
14.
ACS Omega ; 4(24): 20756-20761, 2019 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-31858062

RESUMEN

Herein, we present a solar-blind ultraviolet photodetector realized using atomic layer-deposited p-type cuprous oxide (Cu2O) underneath a mechanically exfoliated n-type ß-gallium oxide (ß-Ga2O3) nanomembrane. The atomic layer deposition process of the Cu2O film applies bis(N,N'-di-secbutylacetamidinato)dicopper(I) [Cu(5Bu-Me-amd)]2 as a novel Cu precursor and water vapor as an oxidant. The exfoliated ß-Ga2O3 nanomembrane was transferred to the top of the Cu2O layer surface to realize a unique oxide pn heterojunction, which is not easy to realize by conventional oxide epitaxy techniques. The current-voltage (I-V) characteristics of the fabricated pn heterojunction diode show the typical rectifying behavior. The fabricated Cu2O/ß-Ga2O3 photodetector achieves sensitive detection of current at the picoampere scale in the reverse mode. This work provides a new approach to integrate all oxide heterojunctions using membrane transfer and bonding techniques, which goes beyond the limitation of conventional heteroepitaxy.

15.
J Magn Reson Imaging ; 47(2): 468-476, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-28639264

RESUMEN

PURPOSE: To compare mono- and bi-exponential relaxation model equations to discriminate between normal and fatty liver disease. MATERIALS AND METHODS: Six rats on a choline deficient amino acid modified (CDAA) diet and six on normal chow were studied. Multiple spin echo images with increasing echo times (TEs) were collected at 9.4T. Pixel-wise T2 maps were generated using mono-exponential decay function to calculate T2M , and a bi-exponential to calculate, short T2 component (T2S ), long T2 component (T2L ), and fractions of these components (ρS , ρL ), respectively. Statistical F-tests and Akaike's information criterion (AIC) were used to assess the relative performance of the two models. RESULTS: F-test and AIC showed that in the CDAA group, T2 bi-exponential model described the signal of T2 weighted imaging of the liver better than the mono-exponential model. Controls were best described by the mono-exponential model. Mean values for T2M , T2L , T2S , ρS , ρL were 31.2 ± 0.7 ms, 72.8 ± 3.3 ms, 8.2 ± 0.6 ms,71.2 ± 2.1%, 30.4 ± 1.3%, respectively, in CDAA rats, compared with 18.8 ± 0.5 ms, 32.3 ± 0.7 ms, 9.2 ± 1.8 ms, 79 ± 2%, 21.0 ± 1.1% in controls. CONCLUSION: In the fatty liver of CDAA rats we have shown that T2 weighted images fit the bi-exponential model better than mono-exponential decays thus providing a better description of the data. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:468-476.


Asunto(s)
Hígado Graso/diagnóstico por imagen , Hígado Graso/patología , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Animales , Modelos Animales de Enfermedad , Hígado/diagnóstico por imagen , Hígado/patología , Fantasmas de Imagen , Ratas
16.
Nano Lett ; 16(12): 7650-7654, 2016 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-27960444

RESUMEN

We demonstrate for the first time that a single-crystalline epitaxial MgxCa1-xO film can be deposited on gallium nitride (GaN) by atomic layer deposition (ALD). By adjusting the ratio between the amounts of Mg and Ca in the film, a lattice matched MgxCa1-xO/GaN(0001) interface can be achieved with low interfacial defect density. High-resolution X-ray diffraction (XRD) shows that the lattice parameter of this ternary oxide nearly obeys Vegard's law. An atomically sharp interface from cross-sectional transmission electron microscopy (TEM) confirmed the high quality of the epitaxy. High-temperature capacitance-voltage characterization showed that the film with composition Mg0.25Ca0.75O has the lowest interfacial defect density. With this optimal oxide composition, a Mg0.25Ca0.75O/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility (MOS-HEMT) device was fabricated. An ultrahigh on/off ratio of 1012 and a near ideal SS of 62 mV/dec were achieved with this device.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...