19 research outputs found
Healthy living on a healthy planet - Summary
Unsere Lebensweise macht krank und zerstört die natürlichen Lebensgrundlagen. In der Vision „Gesund leben auf einer gesunden Erde“ werden menschliche Lebensbereiche – Ernähren, Bewegen, Wohnen – gesund und umweltverträglich gestaltet sowie planetare Risiken – Klimawandel, Biodiversitätsverlust, Verschmutzung – bewältigt. Gesundheitssysteme nutzen ihre transformativen Potenziale, Bildung und Wissenschaft befördern gesellschaftliche Veränderungen. Die Vision ist nur mit internationaler Kooperation realisierbar und erfordert eine globale Dringlichkeitsgovernance.Our lifestyle is making us ill and is destroying the natural life-support systems. In the vision of ‘healthy living on a healthy planet’, human spheres of life – what we eat, how we move, where we live – are designed to be both healthy and environmentally compatible, and planetary risks – climate change, biodiversity loss, pollution – have been overcome. Health systems harness their transformative potential; education and science promote societal change. The vision can only be realized with international cooperation and requires what the WBGU terms global urgency governance
Charge Transport in Single-crystalline CVD Diamond
Diamond is a semiconductor with many superior material properties such as high breakdown field, high saturation velocity, high carrier mobilities and the highest thermal conductivity of all materials. These extreme properties, as compared to other (wide bandgap) semiconductors, make it desirable to develop single-crystalline epitaxial diamond films for electronic device and detector applications. Future diamond devices, such as power diodes, photoconductive switches and high-frequency field effect transistors, could in principle deliver outstanding performance due to diamond's excellent intrinsic properties. However, such electronic applications put severe demands on the crystalline quality of the material. Many fundamental electronic properties of diamond are still poorly understood, which severely holds back diamond-based electronic device and detector development. This problem is largely due to incomplete knowledge of the defects in the material and due to a lack of understanding of how these defects influence transport properties. Since diamond lacks a shallow dopant that is fully thermally activated at room temperature, the conventional silicon semiconductor technology cannot be transferred to diamond devices; instead, new concepts have to be developed. Some of the more promising device concepts contain thin delta-doped layers with a very high dopant concentration, which are fully activated in conjunction with undoped (intrinsic) layers where charges are transported. Thus, it is crucial to better understand transport in high-quality undoped layers with high carrier mobilities. The focus of this doctoral thesis is therefore the study of charge transport and related electronic properties of single-crystalline plasma-deposited (SC-CVD) diamond samples, in order to improve knowledge on charge creation and transport mechanisms. Fundamental characteristics such as drift mobilities, compensation ratios and average pair-creation energy were measured. Comparing them with theoretical predictions from simulations allows for verification of these models and improvement of the diamond deposition process
Charge Transport in Single-crystalline CVD Diamond
Diamond is a semiconductor with many superior material properties such as high breakdown field, high saturation velocity, high carrier mobilities and the highest thermal conductivity of all materials. These extreme properties, as compared to other (wide bandgap) semiconductors, make it desirable to develop single-crystalline epitaxial diamond films for electronic device and detector applications. Future diamond devices, such as power diodes, photoconductive switches and high-frequency field effect transistors, could in principle deliver outstanding performance due to diamond's excellent intrinsic properties. However, such electronic applications put severe demands on the crystalline quality of the material. Many fundamental electronic properties of diamond are still poorly understood, which severely holds back diamond-based electronic device and detector development. This problem is largely due to incomplete knowledge of the defects in the material and due to a lack of understanding of how these defects influence transport properties. Since diamond lacks a shallow dopant that is fully thermally activated at room temperature, the conventional silicon semiconductor technology cannot be transferred to diamond devices; instead, new concepts have to be developed. Some of the more promising device concepts contain thin delta-doped layers with a very high dopant concentration, which are fully activated in conjunction with undoped (intrinsic) layers where charges are transported. Thus, it is crucial to better understand transport in high-quality undoped layers with high carrier mobilities. The focus of this doctoral thesis is therefore the study of charge transport and related electronic properties of single-crystalline plasma-deposited (SC-CVD) diamond samples, in order to improve knowledge on charge creation and transport mechanisms. Fundamental characteristics such as drift mobilities, compensation ratios and average pair-creation energy were measured. Comparing them with theoretical predictions from simulations allows for verification of these models and improvement of the diamond deposition process
Charge Transport in Single-crystalline CVD Diamond
Diamond is a semiconductor with many superior material properties such as high breakdown field, high saturation velocity, high carrier mobilities and the highest thermal conductivity of all materials. These extreme properties, as compared to other (wide bandgap) semiconductors, make it desirable to develop single-crystalline epitaxial diamond films for electronic device and detector applications. Future diamond devices, such as power diodes, photoconductive switches and high-frequency field effect transistors, could in principle deliver outstanding performance due to diamond's excellent intrinsic properties. However, such electronic applications put severe demands on the crystalline quality of the material. Many fundamental electronic properties of diamond are still poorly understood, which severely holds back diamond-based electronic device and detector development. This problem is largely due to incomplete knowledge of the defects in the material and due to a lack of understanding of how these defects influence transport properties. Since diamond lacks a shallow dopant that is fully thermally activated at room temperature, the conventional silicon semiconductor technology cannot be transferred to diamond devices; instead, new concepts have to be developed. Some of the more promising device concepts contain thin delta-doped layers with a very high dopant concentration, which are fully activated in conjunction with undoped (intrinsic) layers where charges are transported. Thus, it is crucial to better understand transport in high-quality undoped layers with high carrier mobilities. The focus of this doctoral thesis is therefore the study of charge transport and related electronic properties of single-crystalline plasma-deposited (SC-CVD) diamond samples, in order to improve knowledge on charge creation and transport mechanisms. Fundamental characteristics such as drift mobilities, compensation ratios and average pair-creation energy were measured. Comparing them with theoretical predictions from simulations allows for verification of these models and improvement of the diamond deposition process
Designing Lesson Plans for Integrated Learning of Home Economics and English in Grade 9
Diplomdarba tēma “Stundu plānu modelēšana mājturības un angļu valodas integrētai mācīšanai 9.klasē”, jo ar mācīšanos tiek saprasta ne tikai mācību priekšmeta apguve. Jāveicina mācīšanās kopveselumā. 21.gadsimta izglītības sistēmai tiek radīti jauni izaicinājumi. CLIL pieeja veicinātu mācību priekšmetu integrēšanu un skolotāju sadarbību.
Metodes: tika izanalizēti avoti par satura un valodas integrētu mācīšanu un stundu plānošanu; tika aptaujāti 9.klases skolēni; tika savākti dati – atgriezeniskā saite par stundās apgūto; tika intervētas divas skolotājas, kuras praksē pielieto CLIL; tika veikta stundu plānu analīze, pēc SIOP modeļa kritērijiem.
Pētījuma secinājumi: ikdienā skolēnu vidū angļu valoda tiek izmantota, kā piemēram, tiek lasītas grāmatas un Internetā atrodamie avoti angļu valodā, kā arī filmas tiek skatītas angļu valodā, tiek klausītas dziesmas angļu valodā. Skolēnu vidū valda uzskats, ka angļu valoda būs vajadzīga turpmākajās mācībās/studijās un veidojot karjeru. Skolēnu interese tiek pievērsta tam,The topic of the Diploma Paper is `Designing Lesson Plans for Integrated Learning of Home Economics and English in Grade 9.` Learning is could not only considered as subject acquiring. Integration between subjects should be developed. New challenges are wakened for 21st century educational system. Subject integration and teacher collaboration could be promoted with CLIL approach.
Methods: sources on content and language integrated learning and lesson planning were examined; questionnaire to Grade 9 students were given, feedback field-notes were collected, interviews with two CLIL practising teachers were held, self-designed lesson plans base on SIOP Model criteria were analysed.
Conclusions from research data: English language is used by students in their daily life, for example, books and online materials are read in English, as well as movies are watched in English and songs are listened in English. It is considered by students, that English language will be needed in their future studies and career. Students interest is paid on how to learn other subjects through English
Electron and hole drift velocity in chemical vapor deposition diamond
The time-of-flight technique has been used to measure the drift velocities for electrons and holes in high-purity single-crystalline CVD diamond. Measurements were made in the temperature interval 83 ≤ T ≤ 460 K and for electric fields between 90 and 4 × 103 V/cm, applied in the <100> crystallographic direction. The study includes low-field drift mobilities and is performed in the low-injection regime to perturb the applied electric field only minimally
Carrier Scattering Mechanisms : Identification via the Scaling Properties of the Boltzmann Transport Equation
A method based on the scaling properties of the Boltzmann transport equation is proposed to identify the dominant scattering mechanisms that affect charge transport in a semiconductor. This method uses drift velocity data of mobile charges at different lattice temperatures and applied electric fields and takes into account the effect of carrier heating. By performing time‐of‐flight measurements on single‐crystalline diamond, hole and electron drift velocities are measured under low‐injection conditions within the temperature range 10–300 K. Evaluation of the data using the proposed method identifies acoustic phonon scattering as the dominant scattering mechanism across the measured temperature range. The exception is electrons at 100–200 K where conduction‐band valley repopulation has a prominent effect. At temperatures below ≈80 K, where valley polarization is observed for electrons, transport dominated by acoustic phonon scattering is observed in different valleys separately. The scaling model is additionally tested on data from highly resistive gallium arsenide samples to demonstrate the versatility of the method. In this case, impurity scattering can be ruled out as the dominant scattering mechanism in the samples for the temperature range 80–120 K
Observation of transferred-electron oscillations in diamond
The transferred-electron oscillator (TEO), or Gunn oscillator, is a device used in microwave applications, which utilizes the negative differential mobility (NDM) effect to generate continuous oscillations. Recently, NDM was observed in intrinsic single-crystalline chemical vapor deposition (SC-CVD) diamond. The occurrence was explained by the electron repopulation between its different conduction band valleys. This paper presents the results of constructing a diamond TEO based on the NDM effect. A series of experiments have been performed for varying voltages, temperatures, and resonator parameters on three SC-CVD diamond samples of different thicknesses. For the temperature range of 90–300 K, we observe transferred-electron oscillations in diamond