Perspectives on MOVPE-grown (100) β-Ga2O3thin films and its Al-alloy for power electronics application

Beta gallium oxide (β-Ga2O3) is a promising ultra-wide bandgap semiconductor with attractive physical properties for next-generation high-power devices, radio frequency electronics, and solar-blind ultraviolet radiation detectors. Here, we present an overview and perspective on the development of MOVPE-grown (100) β-Ga2O3 thin films and its role in supplementing high-power electronics. We review the development path of the growth process on (100) β-Ga2O3 thin films with a discussion regarding the solved and remaining challenges. The structural defect formation mechanism, substrate treatment strategies, and different growth windows are analyzed to optimize the grown film to fulfill the requirements for device fabrication. Toward industrial applications, MOVPE-grown β-Ga2O3 thin films are evaluated in two aspects: thick layers with smooth surface roughness and the electrical properties in terms of high carrier mobility and low doping concentration. Based on the reviewed results, we propose strategies in substrate preparation treatments and supportive tools such as the machine learning approaches for future growth process optimization and envision the rising interest of the β-Ga2O3-related alloy, β-(AlxGa1-x)2O3

High-mobility 4 μm MOVPE-grown (100) β-Ga2O3 film by parasitic particles suppression

In this work, we comprehensively investigate the development of unwanted parasitic particles in the MOVPE chamber while growing μm level films. The density of the parasitic particles is found to be pronounced at film thicknesses starting from >1.5 to 2 μm. These particles seem to induce structural defects such as twin lamellae, thereby harming the electrical properties of the grown film. The origin of the parasitic particle is attributed to the parasitic reactions within the chamber triggered by the promoted gas-phase reactions during the growth process, which can be largely reduced by increasing the total gas flow and decreasing the showerhead distance to the susceptor. A film thickness of up to 4 μm has been achieved after minimizing the density of parasitic particles. Thereby, RT Hall measurements reveal carrier mobilities of 160 cm2V−1s−1 at carrier concentrations of 5.7 × 1016cm−

Suppression of particle formation by gas-phase pre-reactions in (100) MOVPE-grown β -Ga2O3films for vertical device application

This work investigated the metalorganic vapor-phase epitaxy (MOVPE) of (100) β-Ga2O3 films with the aim of meeting the requirements to act as drift layers for high-power electronic devices. A height-adjustable showerhead achieving a close distance to the susceptor (1.5 cm) was demonstrated to be a critical factor in increasing the stability of the Ga wetting layer (or Ga adlayer) on the surface and reducing parasitic particles. A film thickness of up to 3 μm has been achieved while keeping the root mean square below 0.7 nm. Record carrier mobilities of 155 cm2 V-1 s-1 (2.2 μm) and 163 cm2 V-1 s-1 (3 μm) at room temperature were measured for (100) β-Ga2O3 films with carrier concentrations of 5.7 × 1016 and 7.1 × 1016 cm-3, respectively. Analysis of temperature-dependent Hall mobility and carrier concentration data revealed a low background compensating acceptor concentration of 4 × 1015 cm-3

Bulk single crystals and physical properties of β-(AlxGa1-x)2O3(x = 0-0.35) grown by the Czochralski method

We have systematically studied the growth, by the Czochralski method, and basic physical properties of a 2 cm and 2 in. diameter bulk β-(AlxGa1-x)2O3 single crystal with [Al] = 0-35 mol. % in the melt in 5 mol. % steps. The segregation coefficient of Al in the Ga2O3 melt of 1.1-1.2 results in a higher Al content in the crystals than in the melt. The crystals were also co-doped with Si or Mg. [Al] = 30 mol. % in the melt (33-36 mol. % in the crystals) seems to be a limit for obtaining bulk single crystals of high structural quality suitable for homoepitaxy. The crystals were either semiconducting (no intentional co-dopants with [Al] = 0-30 mol. % and Si-doped with [Al] = 15-20 mol. %), degenerately semiconducting (Si-doped with [Al] ≤ 15 mol. %), or semi-insulating ([Al] ≥ 25 mol. % and/or Mg-doped). The full width at half maximum of the rocking curve was 30-50 arcsec. The crystals showed a linear but anisotropic decrease in all lattice constants and a linear increase in the optical bandgap (5.6 eV for [Al] = 30 mol. %). The room temperature electron mobility at similar free electron concentrations gradually decreases with [Al], presumably due to enhanced scattering at phonons as the result of a larger lattice distortion. In Si co-doped crystals, the scattering is enhanced by ionized impurities. Measured electron mobilities and bandgaps enabled to estimate the Baliga figure of merit for electronic devices

Targeted genetic testing for familial hypercholesterolaemia using next generation sequencing:a population-based study

Background<p></p> Familial hypercholesterolaemia (FH) is a common Mendelian condition which, untreated, results in premature coronary heart disease. An estimated 88% of FH cases are undiagnosed in the UK. We previously validated a method for FH mutation detection in a lipid clinic population using next generation sequencing (NGS), but this did not address the challenge of identifying index cases in primary care where most undiagnosed patients receive healthcare. Here, we evaluate the targeted use of NGS as a potential route to diagnosis of FH in a primary care population subset selected for hypercholesterolaemia.<p></p> Methods<p></p> We used microfluidics-based PCR amplification coupled with NGS and multiplex ligation-dependent probe amplification (MLPA) to detect mutations in LDLR, APOB and PCSK9 in three phenotypic groups within the Generation Scotland: Scottish Family Health Study including 193 individuals with high total cholesterol, 232 with moderately high total cholesterol despite cholesterol-lowering therapy, and 192 normocholesterolaemic controls.<p></p> Results<p></p> Pathogenic mutations were found in 2.1% of hypercholesterolaemic individuals, in 2.2% of subjects on cholesterol-lowering therapy and in 42% of their available first-degree relatives. In addition, variants of uncertain clinical significance (VUCS) were detected in 1.4% of the hypercholesterolaemic and cholesterol-lowering therapy groups. No pathogenic variants or VUCS were detected in controls.<p></p> Conclusions<p></p> We demonstrated that population-based genetic testing using these protocols is able to deliver definitive molecular diagnoses of FH in individuals with high cholesterol or on cholesterol-lowering therapy. The lower cost and labour associated with NGS-based testing may increase the attractiveness of a population-based approach to FH detection compared to genetic testing with conventional sequencing. This could provide one route to increasing the present low percentage of FH cases with a genetic diagnosis

Nachhaltigkeit im industriellen Umfeld

Im Rahmen der Lehrveranstaltung "Nachhaltigkeit im industriellen Umfeld" im Masterstudiengang Umwelt- und Verfahrenstechnik der Hochschulen Konstanz und Ravensburg-Weingarten wurde 2015 eine studentische Fachkonferenz durchgeführt. Die Studierenden entwickelten in Einzelarbeit oder als Zweierteam Konferenzbeiträge zu folgenden Themen: - Innovationen und Spannendes aus dem Bereich der Energieerzeugung und -wandlung - Aspekte der Schließung von Stoffkreisläufen und Vermeidung von Schadstoffeinträgen in die Umwelt - Chancen und Herausforderungen Nachwachsender Rohstoffe bei verschiedenen Einsatzmöglichkeiten sowie Themen der Nachhaltigkeit in der Landwirtschaft - verschiedene Blickwinkel auf das Thema Wasser (von der Abwasserreinigung bis zum Wasserkonsum der Konsumenten) - die Betrachtung spezifischer Industrien und Unternehmen sowie deren Werkzeuge zur Umsetzung von Nachhaltigkeit Die Ergebnisse der studentischen Fachkonferenz zur „Nachhaltigkeit im industriellen Umfeld“ werden in der vorliegenden Publikation präsentiert

Fibromyalgia and neuropathic pain - differences and similarities. A comparison of 3057 patients with diabetic painful neuropathy and fibromyalgia

<p>Abstract</p> <p>Background</p> <p>Patients with diabetic neuropathy (DPN) and fibromyalgia differ substantially in pathogenetic factors and the spatial distribution of the perceived pain. We questioned whether, despite these obvious differences, similar abnormal sensory complaints and pain qualities exist in both entities. We hypothesized that similar sensory symptoms might be associated with similar mechanisms of pain generation. The aims were (1) to compare epidemiological features and co-morbidities and (2) to identify similarities and differences of sensory symptoms in both entities.</p> <p>Methods</p> <p>The present multi-center study compares epidemiological data and sensory symptoms of a large cohort of 1434 fibromyalgia patients and 1623 patients with painful diabetic neuropathy. Data acquisition included standard demographic questions and self-report questionnaires (MOS sleep scale, PHQ-9, Pain<it>DETECT</it>). To identify subgroups of patients with characteristic combinations of symptoms (sensory profiles) a cluster analysis was performed using all patients in both cohorts.</p> <p>Results</p> <p>Significant differences in co-morbidities (depression, sleep disturbance) were found between both disorders. Patients of both aetiologies chose very similar descriptors to characterize their sensory perceptions. Burning pain, prickling and touch-evoked allodynia were present in the same frequency. Five subgroups with distinct symptom profiles could be detected. Two of the subgroups were characteristic for fibromyalgia whereas one profile occurred predominantly in DPN patients. Two profiles were found frequently in patients of both entities (20-35%).</p> <p>Conclusions</p> <p>DPN and fibromyalgia patients experience very similar sensory phenomena. The combination of sensory symptoms - the sensory profile - is in most cases distinct and almost unique for each one of the two entities indicating aetiology-specific mechanisms of symptom generation. Beside the unique aetiology-specific sensory profiles an overlap of sensory profiles can be found in 20-35% of patients of both aetiologies.</p

European Language Grid: A Joint Platform for the European Language Technology Community

Europe is a multilingual society, in which dozens of languages are spoken. The only option to enable and to benefit from multilingualism is through Language Technologies (LT), i.e., Natural Language Processing and Speech Technologies. We describe the European Language Grid (ELG), which is targeted to evolve into the primary platform and marketplace for LT in Europe by providing one umbrella platform for the European LT landscape, including research and industry, enabling all stakeholders to upload, share and distribute their services, products and resources. At the end of our EU project, which will establish a legal entity in 2022, the ELG will provide access to approx. 1300 services for all European languages as well as thousands of data sets

European Language Grid: An Overview

With 24 official EU and many additional languages, multilingualism in Europe and an inclusive Digital Single Market can only be enabled through Language Technologies (LTs). European LT business is dominated by hundreds of SMEs and a few large players. Many are world-class, with technologies that outperform the global players. However, European LT business is also fragmented – by nation states, languages, verticals and sectors, significantly holding back its impact. The European Language Grid (ELG) project addresses this fragmentation by establishing the ELG as the primary platform for LT in Europe. The ELG is a scalable cloud platform, providing, in an easy-to-integrate way, access to hundreds of commercial and non-commercial LTs for all European languages, including running tools and services as well as data sets and resources. Once fully operational, it will enable the commercial and non-commercial European LT community to deposit and upload their technologies and data sets into the ELG, to deploy them through the grid, and to connect with other resources. The ELG will boost the Multilingual Digital Single Market towards a thriving European LT community, creating new jobs and opportunities. Furthermore, the ELG project organises two open calls for up to 20 pilot projects. It also sets up 32 national competence centres and the European LT Council for outreach and coordination purposes

CoNLL 2017 Shared Task : Multilingual Parsing from Raw Text to Universal Dependencies

The Conference on Computational Natural Language Learning (CoNLL) features a shared task, in which participants train and test their learning systems on the same data sets. In 2017, one of two tasks was devoted to learning dependency parsers for a large number of languages, in a real world setting without any gold-standard annotation on input. All test sets followed a unified annotation scheme, namely that of Universal Dependencies. In this paper, we define the task and evaluation methodology, describe data preparation, report and analyze the main results, and provide a brief categorization of the different approaches of the participating systems.Peer reviewe