Electronic properties of shallow level defects in ZnO grown by pulsed laser deposition

We have used deep level transient spectroscopy (DLTS) to characterise four defects with shallow levels in ZnO grown by pulsed laser deposition (PLD). These defects all have DLTS peaks below 100 K. From DLTS measurements and Arrhenius plots we have calculated the energy levels of these defects as 31 meV, 64 meV, 100 meV and 140 meV, respectively, below the conduction band. The 100 meV defect displayed metastable behaviour: Annealing under reverse bias at temperatures of above 130 K introduced it while annealing under zero bias above 110 K removed it. The 64 meV and 140 meV defects exhibited a strong electric field assisted emission, indicating that they may be donors

Electronic properties of shallow level defects in ZnO grown by pulsed laser deposition

We have used deep level transient spectroscopy (DLTS) to characterise four defects with shallow levels in ZnO grown by pulsed laser deposition (PLD). These defects all have DLTS peaks below 100 K. From DLTS measurements and Arrhenius plots we have calculated the energy levels of these defects as 31 meV, 64 meV, 100 meV and 140 meV, respectively, below the conduction band. The 100 meV defect displayed metastable behaviour: Annealing under reverse bias at temperatures of above 130 K introduced it while annealing under zero bias above 110 K removed it. The 64 meV and 140 meV defects exhibited a strong electric field assisted emission, indicating that they may be donors

Модернизация конструкции и технологии изготовления герметичного кожуха

Цель работы состоит в усовершенствовании конструкции детали герметичный "кожух" с целью снижения вероятности отклонений его качественных показателей при испытаниях и условиях космических полетов (высокие температура и давление, низкие температуры космического пространства, вибрационные нагрузки на этапе выведения, радиационное воздействие, глубокий вакуум, микрочастицы и т. д.) и иметь низкую удельную массу.The purpose of the work is to improve the design of a hermetically sealed "casing" part in order to reduce the likelihood of deviations in its quality indicators during tests and conditions of space flights (high temperature and pressure, low temperatures of outer space, vibration loads during the launching phase, radiation exposure, deep vacuum, microparticles, etc.) and have a low specific gravity

Room temperature ferromagnetism in carbon-implanted ZnO

Unexpected ferromagnetism has been observed in carbon doped ZnO films grown by pulsed laser deposition [Phys. Rev. Lett. 99, 127201 (2007)]. In this letter, we introduce carbon into ZnO films by ion implantation. Room temperature ferromagnetism has been observed. Our analysis demonstrates that (1) C-doped ferromagnetic ZnO can be achieved by an alternative method, i.e. ion implantation, and (2) the chemical involvement of carbon in the ferromagnetism is indirectly proven.Comment: 13 pages, 3 figs, accepted for publication at Appl. Phys. Let

Podcasting im Musikunterricht. Eine Anwendung der Theorie forschenden Lernens

Viele der bisherigen Podcasting-Anwendungen im Bildungsbereich beschränken sich auf die so genannten „Unterrichtskonserven“ ohne spezifische, mediendidaktische und medienpädagogische Basis. Die vorliegende Arbeit präsentiert eine auf Grund der Theorie forschenden Lernens konzipierte Anwendung des Podcasting. Ausgehend von der Theorie des forschenden Lernens wird eine Lernumgebung entwickelt, die den Musiklernenden einen breiteren Zugang zum Musikunterricht erlaubt. In Zeiten, wenn der Lehrer nicht in greifbarer Nähe ist, kann der Kontakt mit diesem elektronisch vermittelt und durch Kooperation mit Mitlernenden erweitert werden. Dadurch soll der Erwerb von domänenspezifischen und -unspezifischen Wissen und Fertigkeiten unterstützt werden. Neben dem Ausbau musikalischer Fertigkeiten und musikkritischen Wissens soll die Sozial- wie auch die Medienkompetenz ausgebaut werden. Die Podcast-Umgebung bietet eine Ergänzung, keineswegs einen Ersatz des traditionellen Unterrichts. Sie ist als studentische Arbeit im Rahmen des Proseminars „Podcasting in der Aus- und Weiterbildung“ an der Fakultät für Psychologie und Pädagogik der LMU München entstanden. Derzeit wird sie weiterentwickelt; das konkrete Einsatzszenario und die Evaluation der Lernumgebung befinden sich in der Planungsphase. (DIPF/ Orig.

Adaptive Prozessführung für die Zerspanung

Since a direct measurement of occurring process fluctuations, such as tool wear or microstructure and allowance fluctuations, is not possible, it is necessary to use indirect measurement variables for information acquisition. These can be, for example, the torque-forming current of the main spindle or, in machines where several tools are simultaneously engaged (multi-channel machines), such as machines with two tool slides, the torque-forming current of the feed axes. Due to the interaction between the process conditions and the signals evaluated during the process, the process status can be continuously characterized and influenced by the control system. The subject of the invention is a novel system for adaptive process control, which operates on the principle of processing the internal drive signals of machine control systems. With the help of this system, unproductive air cuts due to safeties in approach and overflow paths can be minimized and fluctuations in dimensions and microstructure and process instabilities of the running machining can be detected. This makes it possible to always regulate to the maximum of the permissible process parameters - an optimization of productivity and an increase in process stability are the consequences. Furthermore, continuous monitoring and control allows longer tool life due to the prevention of premature tool wear

Electronic properties of shallow level defects in ZnO grown by pulsed laser deposition

We have used deep level transient spectroscopy (DLTS) to characterise four defects with shallow levels in ZnO grown by pulsed laser deposition (PLD). These defects all have DLTS peaks below 100 K. From DLTS measurements and Arrhenius plots we have calculated the energy levels of these defects as 31 meV, 64 meV, 100 meV and 140 meV, respectively, below the conduction band. The 100 meV defect displayed metastable behaviour: Annealing under reverse bias at temperatures of above 130 K introduced it while annealing under zero bias above 110 K removed it. The 64 meV and 140 meV defects exhibited a strong electric field assisted emission, indicating that they may be donors

Electronic properties of shallow level defects in ZnO grown by pulsed laser deposition

We have used deep level transient spectroscopy (DLTS) to characterise four defects with shallow levels in ZnO grown by pulsed laser deposition (PLD). These defects all have DLTS peaks below 100 K. From DLTS measurements and Arrhenius plots we have calculated the energy levels of these defects as 31 meV, 64 meV, 100 meV and 140 meV, respectively, below the conduction band. The 100 meV defect displayed metastable behaviour: Annealing under reverse bias at temperatures of above 130 K introduced it while annealing under zero bias above 110 K removed it. The 64 meV and 140 meV defects exhibited a strong electric field assisted emission, indicating that they may be donors