Sökning: "STM"

Visar resultat 26 - 30 av 89 avhandlingar innehållade ordet STM.

  1. 26. 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

  2. 27. Electronic and atomic structure of metal induced reconstructionson Si(lll) and Ge(lll) surfaces studied by PES and STM

    Författare :Hanmin M. Zhang; Hanno H. Weitering; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Deposition of metal atoms on semiconductors leads in many cases to reconstructed surfaces. The lack of symmetry in the direction normal to the surface allows for a large variety in the atomic arrangements of the surface reconstructions. In the case of silicon, more than 300 kinds of adsorbate-induced surface reconstructions have been found. LÄS MER

  3. 28. Scanning Tunneling Microscopy Induced Luminescence Studies of Semiconductor Nanostructures

    Författare :Ulf Håkanson; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transmission electron microscopy TEM ; III-V semiconductors; low-dimensional structures; nanostructures; single dot spectroscopy; Stranski-Krastanow; quantum dot QD ; Semiconductory physics; polarization; ordering; InP; GaInP; photon mapping; scanning tunneling microscopy STM ; scanning tunneling luminescence STL ; Halvledarfysik; Fysicumarkivet A:2003:Håkanson;

    Sammanfattning : This thesis treats scanning tunneling luminescence (STL) investigations of semiconductor nanostructures. The STL technique combines scanning tunneling microscopy (STM) with detection of photons, induced by the tunneling electrons. The high spatial resolution in STM and the local excitation allow for optical investigations on the nanometer-scale. LÄS MER

  4. 29. Phthalocyanines on Surfaces : Monolayers, Films and Alkali Modified Structures

    Författare :Katharina Nilson; Carla Puglia; Joachim Schiessling; Emmanuelle Göthelid; Nils Mårtensson; Guy Le Lay; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; Phthalocyanines; Surface Science; X-ray Photoelectron Spectroscopy XPS ; X-ray Absorption Spectroscopy XAS ; Scanning Tunneling Microscopy STM ; Density Functional Theory DFT ; Metal-free Phthalocyanine; Iron Phthalocyanine; Zinc Phthalocyanine; Gold; Graphite; Aluminium; Indium Antimony; Molecular adsorption; Monolayer; Film; Alkali; Geometrical structure; Electronic structure; Doping; Atom- och molekylfysik; Physics; Fysik;

    Sammanfattning : The Phthalocyanines (Pc’s) are a group of macro-cyclic molecules, widely investigated due to the possibility to use them in a variety of applications. Electronic and geometrical structure investigations of molecular model systems of Pc’s adsorbed on surfaces are important for a deeper understanding of the functionality of different Pc-based devices. LÄS MER

  5. 30. Electronic and Geometrical Structure of Phthalocyanines on Surfaces : An Electron Spectroscopy and Scanning Tunneling Microscopy Study

    Författare :John Åhlund; Carla Puglia; Joachim Schiessling; Emanuelle Göthelid; Nils Mårtensson; Nadine Witkowski; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; PhotoElectron Spectroscopy PES ; X-ray Absorption Spectroscopy XAS ; UltraViolet-Visible absorption spectroscopy UV-Vis ; Scanning Tunneling Microscopy STM ; Phthalocyanine Pc ; Iron Phthalocyanine FePc ; metal-free Phthalocyanine H2Pc ; Zinc Phthalocyanine ZnPc ; Graphite HOPG ; Indium Antimony InSb ; Surface science; Fysik;

    Sammanfattning : Core- and Valence Photoelectron Spectroscopy (PES), X-ray- and Ultraviolet-Visible Absorption Spectroscopy (XAS and UV-Vis), Scanning Tunneling Microscopy (STM) and Density Functional Theory (DFT) calculations are used to study the electronic and geometrical structure of a class of macro-cyclic molecules, Phthalocyanines (Pc), on surfaces. These molecules are widely studied due to their application in many different fields. LÄS MER