Sökning: "trapping effects"

Visar resultat 1 - 5 av 77 avhandlingar innehållade orden trapping effects.

  1. 1. Buffer Related Dispersive Effects in Microwave GaN HEMTs

    Författare :Johan Bergsten; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; trapping effects; C-doping; AlGaN GaN interface quality; recessed ohmic contacts; GaN HEMT; buffer design;

    Sammanfattning : In applications such as mobile communication and radar, microwave power generation at high frequency is of utmost importance. The GaN HEMT offers a unique set of properties that makes it suitable for high power amplification at high frequencies. LÄS MER

  2. 2. Nonlinear Characterization of Wideband Microwave Devices and Dispersive Effects in GaN HEMTs

    Författare :Sebastian Gustafsson; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; large-signal; dispersive effects; electron trapping; thermal coupling; HEMT; GaN; microwave; wideband;

    Sammanfattning : Measurements play a key role in the development of microwave hardware as they allow engineers to test and verify the RF performance on a system, circuit, and component level. Since modern cellular standards employ complex modulation formats with wider signal bandwidths to cope with the growing demand of higher datarates, nonlinear characterization using wideband stimuli is becoming increasingly important. LÄS MER

  3. 3. Residual and Solubility trapping during Geological CO2 storage : Numerical and Experimental studies

    Författare :Maria Rasmusson; Fritjof Fagerlund; Auli Niemi; Jonathan Ennis-King; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; capillary trapping; CCS; convective flow; CO2; light transmission; SO2; well test; Hydrology; Hydrologi;

    Sammanfattning : Geological storage of carbon dioxide (CO2) in deep saline aquifers mitigates atmospheric release of greenhouse gases. To estimate storage capacity and evaluate storage safety, knowledge of the trapping mechanisms that retain CO2 within geological formations, and the factors affecting these is fundamental. LÄS MER

  4. 4. Influence of Self-trapping, Clamping and Confinement on Hydrogen Absorption

    Författare :Gunnar Karl Pálsson; Björgvin Hjörvarsson; Keith Ross; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; hydrogen diffusion; thin films; superlattices; phase transitions; confinement; clamping; self-trapping; finite-size effect; Surfaces and interfaces; Ytor och mellanytor; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The dissociation of hydrogen molecules at surfaces is the first step in the absorption process. If the absorbing material is covered by an oxide, this layer will determine the effective uptake rate of an underlying absorbing material. LÄS MER

  5. 5. Characterization and Compensation of Thermal Effects in GaN HEMT Technologies

    Författare :Johan Bremer; Chalmers University of Technology; []
    Nyckelord :electrothermal; temperature compensation.; AlGaN GaN; thermal coupling; characterization; thermal effects; thermal resistance;

    Sammanfattning : Further advancements with GaN based technologies relies on the ability to handle the heat flux, which consequently arises from the high power density. Advanced cooling techniques and thermal optimization of the technology are therefore prioritized research areas. LÄS MER