Sökning: "and intrinsic defects"

Visar resultat 1 - 5 av 87 avhandlingar innehållade orden and intrinsic defects.

1. 1. Growth and characterization of SiC and GaN

   Författare :Rafal Ciechonski; Erik Janzén; Sebastian Lourdudoss; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SiC; GaN; Deep level transient spectroscopy; Minority Carrier Transient Spectroscopy; Hall effect; Cathodoluminescence; Scanning electron microscopy; Atomic Force microscopy; sublimation growth; MOCVD; heterostructures; High Electron Mobility transistor; point defects; Material physics with surface physics; Materialfysik med ytfysik;

   Sammanfattning : At present, focus of the SiC crystal growth development is on improving the crystalline quality without polytype inclusions, micropipes and the occurrence of extended defects. The purity of the grown material, as well as intentional doping must be well controlled and the processes understood. LÄS MER

3. 2. Atomic Scale Design of Clean Energy Materials : Efficient Solar Energy Conversion and Gas Sensing

   Författare :Jawad Nisar; Rajeev Ahuja; Puru Jena; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Photocatalysts; Band gap narrowing; Water dissociation; Density functional theory; Gas sensing; Kaolinite; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : The focus of this doctoral thesis is the atomic level design of photocatalysts and gas sensing materials. The band gap narrowing in the metal oxides for the visible-light driven photocatalyst as well as the interaction of water and gas molecules on the reactive surfaces of metal oxides and the electronic structure of kaolinite has been studied by the state-of-art calculations. LÄS MER

4. 3. Defect Induced Room-Temperature Ferromagnetism in ZnO and MgO Thin FIlms and Device Development

   Författare :Mukes Kapilashrami; Lyuba Belova; E Dan Dahlberg; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Room-temperature ferromagnetism; intrinsic defects; un-balanced balanced magnetron sputtering; magnetic anisotropy and photoconductivity; Materials science; Teknisk materialvetenskap;

   Sammanfattning : This thesis presents the discovery of defect induced room-temperature ferromagnetism in industrially important ZnO and MgO thin films, and establishes from a systematic study, in both ZnO and MgO films, the unique phenomenon of the sequences of transitions from ferromagnetism to para-, and eventually the well known diamagnetism of the bulk as a function of film thickness. Highly oriented and high quality dense thin films of ZnO and MgO have been deposited by reactive (balanced) magnetron sputtering under different ambience conditions and deposition temperatures. LÄS MER

5. 4. Laser Based Powder Bed Fusion of Plain Carbon and Low-Alloy Steels: Microstructure and Processability

   Författare :William Hearn; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Low-Alloy Steel; Additive Manufacturing; Lack of Fusion Porosity; Laser Based Powder Bed Fusion; Plain Carbon Steel; Intrinsic Heat Treatment; Keyhole Porosity; Cold Cracking;

   Sammanfattning : Despite the prominence of laser based powder bed fusion (LB-PBF) as an additive manufacturing technique, the number of alloys that have been approved for the process remains limited. In traditional manufacturing, ferrous alloys are the most common alloy group, consisting primarily of plain carbon and low-alloy steels. LÄS MER

7. 5. Materials prepared using graphite oxides : properties and applications

   Författare :Artem Iakunkov; Aleksandr V. Talyzin; Josef Breu; Umeå universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Graphene oxide; Activated Graphene; Swelling; Supercapacitor; Sorption of radionuclides; Materials Science; materialvetenskap; fysik; Physics;

   Sammanfattning : Graphite oxides are hydrophilic materials, which have attracted a lot of attention due to unique properties and possible applications. The current thesis includes studies of fundamental properties and applications of graphite oxides as well as materials prepared from graphite oxides such as graphene oxide membranes, defect-rich graphite oxide, reduced graphene oxide and activated reduced graphene oxide. LÄS MER