Sökning: "scanning tunneling microscopy"

Visar resultat 1 - 5 av 70 avhandlingar innehållade orden scanning tunneling microscopy.

  1. 1. Theoretical modeling of scanning tunneling microscopy

    Författare :Alexander Gustafsson; Magnus Paulsson; Jorge Iribas Cerdá; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scanning tunneling microscopy; Computational models; Quantum tunneling; Green s functions; Density functional theory; Condensed Matter Physics; Kondenserade materians fysik;

    Sammanfattning : The main body of this thesis describes how to calculate scanning tunneling microscopy (STM) images from first-principles methods. The theory is based on localized orbital density functional theory (DFT), whose limitations for large-vacuum STM models are resolved by propagating localized-basis wave functions close to the surface into the vacuum region in real space. LÄS MER

  3. 2. 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. 3. 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

  5. 4. The Cu(111) surface studied by scanning tunnelling microscopy and spectroscopy

    Författare :Erik Wahlström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cu 111 ; surface states; tungsten tips; scanning tunneling spectroscopy; scanning tunneling microscopy; adsorbate interaction;

    Sammanfattning : .... LÄS MER

  7. 5. Modeling of non-equilibrium scanning probe microscopy

    Författare :Alexander Gustafsson; Magnus Paulsson; Tchavdar Todorov; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; scanning tunneling microscopy; molecular dynamics; density functional theory; non-equilibrium Green s functions; Condensed Matter Physics; Kondenserade materians fysik;

    Sammanfattning : The work in this thesis is basically divided into two related but separate investigations.The first part treats simple chemical reactions of adsorbate molecules on metallic surfaces, induced by means of a scanning tunneling probe (STM). The investigation serves as a parameter free extension to existing theories. LÄS MER