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Showing 1 to 14 of 14 for “"Galliumnitrid"”.
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Magnetische Halbleiter zum Einsatz in der Spinelektronik : Europiumsulfid und magnetisch dotiertes Galliumnitrid
In this work, magnetic semiconductors were investigated. The work on magnetic semiconductors is motivated by the great interest in the field of spinelectronics in recent years. Of particular interest are magnetic semiconductors which are ferromagnetic with Curie-temperatures well above room …
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Variation von Kristallinität und Stöchiometrie in mittels PLD hergestellten Schichten aus Galliumoxid, Galliumnitrid und Bariumzirkonat
Pulsed Laser Deposition (PLD) is an ablation technique for thin film preparation of many materials. The film properties can be well controlled by the process parameters. Therefore, in many cases a given material can be deposited with different properties by changing one or more process parameters. …
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Persistente Photoleitfähigkeit indünnen GaN- und AlGaN-Schichten
Galliumnitrid (GaN) wird In den nächsten Jahren Im Bereich optoelektronischer Anwendungen das dominierende Materialsystem für Bauteile wie Leuchtdioden und Halbleiterlaserdioden kurzwelligen (blau bis ultraviolett) sein. Rahmen dieser Arbeit untersuche ich Phänomen der persistenten …
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Linear optical properties of III-nitride semiconductors between 3 and 30eV
… Hintergründe diskutiert. Untersucht werden dazu Galliumnitrid (GaN), Indiumnitrid (InN) und Aluminiumnitrid (AlN) sowohl in der stabilen hexagonalen Wurtzit-Kristallstruktur als auch in der metastabilen kubischen Zinkblende-Kristallstruktur. Diesen Materialien gilt seit einigen Jahren ein enormes …
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Fabrication and characterisation of AlGaN/GaN high electron mobolity transistors for power applications
The III-Nitrides were intensively studied during the last few years due to its tunable band gap range from 0.7 eV for InN to 6.2 eV for AlN. In comparison to other systems III-Nitrides have a much smaller lattice constant and therefore are mechanically stable materials with high breakdown fields. …
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Fabrication and characterization of AlGaN/GaN high electron mobility transistors
The task of this work was to fabricate and characterize AlGaN/GaN HEMTs on sapphire and silicon substrates. For this reason the HEMT fabrication technology had to be developed and optimized on AlGaN/GaN heterostructures grown on sapphire and silicon substrates. The optimization of AlGaN/GaN …
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Wachstum und Realstruktur von epitaktischen (Al,Ga)N-Schichten
In der vorliegenden Arbeit wird der Einfluss der Wachstumsparameter auf die Realstruktur von binären GaN-, AlN- und ternären (Al,Ga)N-Schichten untersucht. Die Abscheidung der Schichten erfolgte heteroepitaktisch mittels Molekularstrahlepitaxie (MBE) auf den Substraten Al2O3 (0001), Si (111) und …
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Elektrischer Transport in GaN- und InN-Nanodrähten
This thesis discusses the analysis of the electrical transport in GaN and InN nanowires at room temperature and deep temperatures. From those measurements two different transport models for those two in matter of the band banding completely different materials have been found. To perform those …
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AlGaN/GaN MBE 2DEG heterostructures : interplay between surface-, interface- and device-properties
Due to their wide band gap and high bond strength, the III-N semiconductors can be used for violet, blue and green light emitting devices as well as for high temperature and high power transistors. In comparison to conventional AlGaAs/GaAs heterostructures the AlGaN/GaN material system offers new …
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Characterization of Novel Pyroelectrics
The change of the spontaneous polarization due to a change of temperature is known as the pyroelectric effect and is restricted to crystalline, non-centrosymmetric and polar matter. Its main application is the utilization in infrared radiation sensors, but usage for waste heat energy harvesting or …
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Einfluss der Schichteigenschaften auf das elektrische und optoelektrische Verhalten von AlGaN-GaN-HEMT-Transistoren
The mismatch of the lattice constants and of the thermal expansion coefficients between gallium nitride (GaN) and its substrates like sapphire, silicon and silicon carbide is responsible for a high concentration of defects in AlGaN/GaN layers. The influence of these electrically active centres …
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Investigation of 'high-k' materials as alternative dielectrics for AlGaN/GaN-based metal-insulator-semiconductor heterostructure field effect transistors (MISHFET)
Gallium Nitride (GaN) based heterostructure field-effect transistors (HFET) are promising devices for high-power applications at high frequencies, as to be found in communication technology. The devices benefit from the properties GaN has to offer, namely a wide bandgap, a high carrier mobility and …
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Design and development of radiation-resistant and low-noise semiconductor transistors for applications in high frequency communication systems
In the frame of this work, the fundamental properties of GaN/AlGaN HEMT structures have been investigated in order to optimize their performance in high power microwave devices. A number of properties have been studied, starting from DC transport properties in bare 2DEG channels up to investigation …