Search for dissertations about: "Buffer layer"

Showing result 21 - 25 of 96 swedish dissertations containing the words Buffer layer.

  2. 21. Optimization of Ohmic Contacts and Surface Passivation for ‘Buffer-Free’ GaN HEMT Technologies

    Author : Chen Ding Yuan; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; QuanFINE; passivation; GaN HEMT; pretreatment; ohmic contact;

    Abstract : Gallium nitride high electron mobility transistors (GaN HEMTs) draw attention from high frequency and high power industries due to unique properties including high electron mobility and saturation velocity combined with high breakdown voltage. This makes GaN HEMTs suitable for power devices with high switching speed and high frequency applications with high power density requirements. READ MORE

  4. 22. Green liquor dregs as sealing layer material to cover sulphidic mine waste deposits

    Author : Maria Mäkitalo; Josef Mácsik; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

    Abstract : Waste rock and tailings generated by sulphide ore mining often contains large amounts of iron sulphides which oxidize when exposed to atmospheric oxygen and may generate acidity. In the absence of alkaline minerals to neutralize this acidity, elements including harmful heavy metals become mobile. READ MORE

  5. 23. Band Alignment Between ZnO-Based and Cu(In,Ga)Se2 Thin Films for High Efficiency Solar Cells

    Author : Charlotte Platzer-Björkman; Lars Stolt; John Kessler; Ayodhya Tiwari; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronics; solar cells; Cu In Ga Se2; atomic layer deposition; ZnO; Zn O S ; Zn Mg O; band alignment; photoelectron spectroscopy; Elektronik; Electronics; Elektronik;

    Abstract : Thin-film solar cells based on Cu(In,Ga)Se2 contain a thin buffer layer of CdS in their standard configuration. In order to avoid cadmium in the device for environmental reasons, Cd-free alternatives are investigated. READ MORE

  6. 24. The Bentonite Barrier - Swelling Properties, Redox Chemistry and Mineral Evolution

    Author : Daniel Svensson; Centrum för analys och syntes; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; montmorillonite; bentonite; smectite; freezing; thawing; hydration; intercalation; four-water-layer; ethylene glycol; X-ray diffraction; time-resolved; spatial-resolution; XANES; Fe; redox; iron; ABM; TBT; Äspö;

    Abstract : Bentonite is planned for use as a buffer material in high-level radioactive waste repositories, where safety assessment is performed for very long periods (100-1000 ka). This thesis focuses on the swelling of smectites in liquid water, and analysis of bentonite from field experiments at Äspö Hard Rock Laboratory, Sweden. READ MORE

  7. 25. Hydrodynamics and Complete Suspension in Axially Stirred Vessels

    Author : Claes Sturesson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; axially stirred tank; particle force balances; complete suspension; turbulence modeling; turbulent boundary layer; LDA;

    Abstract : Complete suspension of solid particles in stirred vessels has been subject to numerous investigationsin order to develop appropriate design criteria for solid/liquid suspensions. Previous work on this matter has often suffered from the lack of knowledge of fluid mechanics in the system and models based on overall flow characteristics have been proposed in the literature. READ MORE