Sökning: "metal quantum wells"

Visar resultat 1 - 5 av 18 avhandlingar innehållade orden metal quantum wells.

1. 1. Photoemission from Alkali Metal Overlayers: Quantum Wells, Photoelectron Interference and Atomic Structure Changes

   Författare :Dan Claesson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum well states; surface structure; alkali metals; angle resolved photoemission; surface electronic phenomena; thin films; collective excitations; electronic structure;

   Sammanfattning : Angle resolved photoelectron spectroscopy is used to investigate alkali metal overlayers on noble metal surfaces. The work deals with interference in photoemission, bulk electronic structure and adsorption induced changes of atomic structure, respectively. The relative importance of surface and bulk in photoemission has remained largely unexplored. LÄS MER

3. 2. Interferences in valence-electron photoemission observed via cross sections and line shapes for metal overlayer quantum well states and resonances

   Författare :Dan Claesson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; alkali metals; thin films; angle resolved photoemission; surface electronic phenomena; quantum wells;

   Sammanfattning : .... LÄS MER

4. 3. Type-II interband quantum dot photodetectors

   Författare :Oscar Gustafsson; Mattias Hammar; Wenquan Ma; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; photodetector; quantum dot; infrared; MOVPE; thermal imaging; type-II; photoluminescence; III V; InSb; InGaSb; InAs; SRA - ICT; SRA - Informations- och kommunikationsteknik;

   Sammanfattning : Photon detectors based on single-crystalline materials are of great interest for high performance imaging applications due to their low noise and fast response. The major detector materials for sensing in the long-wavelength infrared (LWIR) band (8-14 µm) are currently HgCdTe (MCT) and AlGaAs/GaAs quantum wells (QW) used in intraband-based quantum-well infrared photodetectors (QWIPs). LÄS MER

5. 4. Scanning Tunnelling Microscopy Studies of Na Islands on Graphite, Impurity Interactions on Cu(111) and Low Temperature Structures of S/Cu(111)

   Författare :Erik Wahlström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; photoelectron spectroscopy; Scanning tunnelling microscopy STM ; Na HOPG; scanning tunnelling spectroscopy STS ; metal quantum wells; surface impurity interaction; S Cu 111 ;

   Sammanfattning : A scanning tunnelling microscope (STM) can reveal the atomic order of a surface as well as details of its electronic structure. In the present work STM, in combination with core and valence photo-electron spectroscopy and low energy electron diffraction (LEED) was applied to three different systems: (i) simple metal quantum wells in the form of Na films and islands on highly oriented pyrolytic graphite (HOPG), (ii) low temperature S/Cu(111) structures discovered in the course of this work and (iii) impurities on Cu(111). LÄS MER

7. 5. Epitaxy of GaAs-based long-wavelength vertical cavity lasers

   Författare :Carl Asplund; KTH; []
   Nyckelord :gainnas; ingaas; quantum wells; movpe; mocvd; vertical cavity laser; bcsel; long-wavelength; epitaxy; xrd; dbr;

   Sammanfattning : Vertical cavity lasers (VCLs) are of great interest aslow-cost, high-performance light sources for fiber-opticcommunication systems. They have a number of advantages overconventional edge-emitting lasers, including low powerconsumption, efficient fiber coupling and wafer scalemanufacturing/testing. LÄS MER