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Probing of Nanostructured Surfaces at Attosecond Timescales

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Based in Birmingham for my first year then at Imperial College London to ... Produce 1x1 reconstructed flat surface and investigate ESD at Birmingham ... – PowerPoint PPT presentation

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Title: Probing of Nanostructured Surfaces at Attosecond Timescales


1
Probing of Nanostructured Surfaces at Attosecond
Timescales
  • Emma Catton
  • 1st year PhD student in the Atomic Manipulation
    Group at NPRL
  • Based in Birmingham for my first year then at
    Imperial College London to concentrate work on
    the STM.

NPRL Nanoscale Physics Research Laboratory
2
Current Group Interests
  • Gold Fingers
  • Finger like structures were produced by scanning
    the STM tip at a step edge with constant voltage
    bias and increasing tunnel current.
  • Fingers were produced at 90 and 150 to the
    discommensuration lines of the heringbone
    reconstruction1.
  • Other Work
  • Dissociation of aromatic molecules on silicon
    surfaces.
  • Manipulation of gold clusters on graphite.
  • Metal oxide semiconductors.

(150nm x 150nm)
Finger Width 3nm - 8nm
1 Q. Guo, F. Yin, R. Palmer, small (1) 76-79
(2005)
NPRL Nanoscale Physics Research Laboratory
3
Proposed Work TiO2 (110) Surface
  • Why TiO2?
  • Considerably well studied in the past the surface
    is now well characterised. This makes it a good
    choice for studying new phenomena.
  • Many applications including photocatalyst, solar
    cells, white pigment, corrosion-protective
    coating and optical coating.
  • Irradiation by electrons or photons can give rise
    to desorption of O ions from the surface via the
    Knotek-Feibelman process. Known as electron or
    photon stimulated desorption (ESD or PSD).
  • Proposed work
  • Produce 1x1 reconstructed flat surface and
    investigate ESD at Birmingham
  • STM studies of surface before and after laser
    irradiation. Possible PSD?
  • Deposit metal such as Au onto surface. Gold is
    expected to diffuse to oxygen deficient sites.
  • Nanostructures can be created.

NPRL Nanoscale Physics Research Laboratory
4
Nanostructured Surfaces
  • Consider a thin film
  • Acts as 1D quantum well
  • Quantum states can be studied using STS (Scanning
    Tunneling Spectroscopy) or photoemission
    spectroscopy.
  • Pump and probe technique can be used to determine
    the lifetime of excited states. Electrons can be
    looked at in real time by varying time delay
    between pulses.
  • Aim of my PhD
  • To combine fast photon pulses and STM allowing
    analysis of surface processes at high spatial and
    temporal resolutions. This will provide a better
    understanding of the dynamical processes of atoms
    and electrons on solid surfaces.

1-2 nm
50nm
50nm
NPRL Nanoscale Physics Research Laboratory
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