Avancerad sökning

Hittade 5 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Cathodoluminescence Studies of Quantum Structures and III-V nitrides

    Författare :Anders Petersson; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AlGaN; Fysik; Physics; GaN-AlGaN; single dot spectroscopy; InP-GaInP; Stranski Krastanow; quantum dots; quantum wires; low-dimensional structures; InAs-GaAs; III-V nitride; Cathodoluminescence; III-V semiconductors; Fysicumarkivet A:1999:Petersson;

    Sammanfattning : Characterization of low-dimensional semiconductor structures is a challenging task. The thesis is based on experiments, using cathodoluminescence (CL) as a tool for characterization. The high spatial resolution and the possibility of spectroscopy of small structures make CL one of the most powerful techniques for these types of investigations. LÄS MER

  3. 2. GaN, AlGaN, GaNAs and Related Heterostructures Grown by Molecular Beam Epitaxy

    Författare :Hyonju Kim; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; surface segregation; GaNAs; plasma-assisted MBE; stacking fault; AlGaN GaN; heterointerface; unintentional impurities; III-nitrides;

    Sammanfattning : This work deals with growth and characterization of III-nitrides and related heterostructures as well as GaNAs alloys grown by plasma assisted molecular beam epitaxy (MBE). The III-nitrides belong to the wide bandgap semiconductors due to their large energy bandgap spanning from 1.9 to 6.2 eV. LÄS MER

  4. 3. Photoluminescence studies of the electronic structure in some III-V quantum structures

    Författare :Joakim Dalfors; Jacques Pankove; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Semiconductor compound materials from groups III and V in the periodic table have attracted much interest during recent years, due to promising properties for optoelectronic devices such as lasers and light emitting diodes. Most of these devices are fabricated from quantum well (QW) structures. LÄS MER

  5. 4. Buffer Related Dispersive Effects in Microwave GaN HEMTs

    Författare :Johan Bergsten; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; 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

  7. 5. High-speed optical modulators based on intersubband transitions

    Författare :Petter Holmström; KTH; []
    Nyckelord :;

    Sammanfattning : Optical modulators are essential components in high speedoptical communication. They are employed to circumvent theinherent speed limitations of direct modulated semiconductorlasers, and may also extend the transmission distance onoptical fibers by providing optical pulses with lowerchirp. LÄS MER