Sökning: "Wide band gap"

Visar resultat 1 - 5 av 71 avhandlingar innehållade orden Wide band gap.

  1. 1. Optical characterization of wide band gap materials by spectroscopic ellipsometry

    Författare :O. P. Alexander Lindquist; Linköpings universitet; []
    Nyckelord :Wide Band Gap materials; ellipsometry; SiC; GaN;

    Sammanfattning : Spectroscopic ellipsometry has been employed in the study of wide band gap materials. Ellipsometry is based on the study of changes in the polarization state of light upon reflection on a surface. LÄS MER

  3. 2. EM Design for New Ultra Wide Band Technologies: Eleven Feed Baluns, Bowtie Antennas and Gap Waveguides

    Författare :Syed Hasan Raza Zaidi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-wideband; Eleven feed; gap waveguide; baluns; Multiport feeding network; power divider; ring hybrid.; packaging;

    Sammanfattning : UWB (ultra wideband), depending on the application requirement, is usually referred to more than 500 MHz bandwidth for radio/wireless applications. Here in this thesis it is also used to denote extremely wideband antennas and components of several octaves bandwidth, particularly for high frequency applications. LÄS MER

  4. 3. Growth and Characterization of Metastable Wide Band-Gap Al1-xInxN Epilayers

    Författare :Timo Seppänen; Robert F. Davis; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Thin film; Magnetron Sputter Epitaxy MSE ; Physics; Fysik;

    Sammanfattning : InN to 6.2 eV for AlN, which opens possibilities to engineer opto-electronic devices operating from infra-red to deep ultra-violet wavelengths. Al1-xInxN with the alloy composition x~0.2 can also be used as a lattice-matched electron confinement layer for GaN based electronic devices. LÄS MER

  5. 4. Extreme Implementations of Wide-Bandgap Semiconductors in Power Electronics

    Författare :Juan Colmenares; Hans-Peter Nee; Leon M. Tolbert; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cryogenic; Gallium Nitride; Gate Driver; Harsh Environments; High Efficiency Converter; High Temperature; MOSFETs; Normally- ON JFETs; Reliability; Silicon Carbide; Wide-Band Gap Semiconductors; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Wide-bandgap (WBG) semiconductor materials such as silicon carbide (SiC) and gallium-nitride (GaN) allow higher voltage ratings, lower on-state voltage drops, higher switching frequencies, and higher maximum temperatures. All these advantages make them an attractive choice when high-power density and high-efficiency converters are targeted. LÄS MER

  7. 5. Everything is imperfect: Studies on point defects in insulators

    Författare :Christopher Linderälv; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boron nitride; band alignment; oxygen vacancies; insulator; optical lineshape; point defects; density functional theory; wide band gap oxides;

    Sammanfattning : Point defects can be detrimental or absolutely necessary for the performance of a material. Due to the implications defects have on a material, defects have been widely studied over the last century. LÄS MER