Sökning: "Bandgap"

Visar resultat 11 - 15 av 191 avhandlingar innehållade ordet Bandgap.

  1. 11. Thermal conductivity of wide and ultra-wide bandgap semiconductors

    Författare :Dat Tran; Plamen Paskov; Vanya Darakchieva; Martin Kuball; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; III-nitrides; β-Ga2O3; Thermal conductivity; Thermal transport;

    Sammanfattning : This PhD thesis presents experimental and theoretical studies of the thermal conductivity of wide and ultra-wide bandgap semiconductors including GaN, AlN, β-Ga2O3 binary compounds, and AlxGa1−xN, ScxAl1−xN, YxAl1−xN ternary alloys. Thermal conductivity measurements are conducted using the transient thermoreflectance (TTR) technique and the results are interpreted using analytical models based on the solution of the Boltzmann transport equation (BTE) within the relaxation time approximation (RTA). LÄS MER

  3. 12. 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

  4. 13. Synthesis and Tuning of Multifunctional Materials at High Pressure

    Författare :Lei Liu; Peter Lazor; Roland Mathieu; Guoyin Shen; Viktor Struzhkin; Ronald Miletich-Pawliczek; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; double perovskite; multiferroic; bandgap engineering; high-entropy alloy; high pressure; Geovetenskap med inriktning mot mineralogi; petrologi och tektonik; Earth Science with specialization in Mineral Chemistry; Petrology and Tectonics;

    Sammanfattning : At the present stage, human society is developing at an unprecedented speed, facing an emergence of highly pressing challenges, e.g., information explosion, energy production problems, environmental pollution, climate problems. Functional materials with tailored properties are considered as holding a key to solving these problems. LÄS MER

  5. 14. High-Temperature Analog and Mixed-Signal Integrated Circuits in Bipolar Silicon Carbide Technology

    Författare :Raheleh Hedayati; Carl-Mikael Zetterling; H. Alan Mantooth; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; silicon carbide SiC ; bipolar junction transistor BJT ; high temperature; SiC integrated circuit; Spice Gummel-Poon SGP ; operational amplifier opamp ; negative feedback amplifier; bandgap reference; masterslave comparator; digital-to-analog converter DAC ; analog-to-digital converter ADC ; flash ADC; successive approximation register SAR ADC; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Silicon carbide (SiC) integrated circuits (ICs) can enable the emergence of robust and reliable systems, including data acquisition and on-site control for extreme environments with high temperature and high radiation such as deep earth drilling, space and aviation, electric and hybrid vehicles, and combustion engines. In particular, SiC ICs provide significant benefit by reducing power dissipation and leakage current at temperatures above 300 °C compared to the Si counterpart. LÄS MER

  7. 15. Surface Energy Patterning and Optoelectronic Devices Based on Conjugated Polymers

    Författare :Xiangjun Wang; Olle Inganäs; Henning Sirringhaus; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Surface energy modification; Patterning; Dewetting; Conjugated polymer; plastic solar cell; Low bandgap; Electron acceptors and donors; Physics; Fysik;

    Sammanfattning : The work presented in this thesis concerns surface energy modification and patterning of the surfaces of conjugated polymers. Goniometry and Wilhelmy Balance techniques were used to evaluate the surface energy or wettability of a polymer’s surface; infrared reflectionabsorption spectroscopy (IRAS) was used to analyse the residuals on the surface as modified by a bare elastomeric stamp poly(dimethylsiloxane) (PDMS). LÄS MER