I have just finished a PhD in theoretical physics, working in the Theoretical Semiconductor Physics Group under the supervision of Dr. Bob Jones.
The aim of my PhD was the study of deep-level defects in semiconductors, in particular, silicon.
I am still personally involved in the following projects:

  • Transition-metal-related defects in Si

    • Isolated substitutional and interstitial defects

    • The interaction of atomic hydrogen with transition-metal impurities.

      Using a Local Density Functional cluster method (see below) with an empirical correction, we can extract the donor and acceptor levels with an accuracy of around 0.2 eV. This allows the characterisation of defects responsible for deep traps observed by capacitance measurements (e.g., DLTS or Laplace DLTS).

    • Transition-metal pairs: Au-Au & Au-Fe

  • Vacancy related defects in Si

    • The study of the structure of the lattice mono-vacancy in 5 different charge states. The meta-stability of the positively charged state (D2d) is analysed.

    • The structural and electrical properties of the lattice di-vacancy. The models by Watkins & Corbett (rebonding-by-pairs) and Saito & Oshiyama (resonant-bond model) are to be compared, using a very large cluster of 386 atoms.

    • The structural and electrical properties of defects in irradiated & implanted silicon:

      • The vibrational and electrical properties of vacancy-Hn complexes (n = 1, 2, 3 and 4)

        Animated 3D-wavefunction isosurface corresponding to the highest
        occupied spin-up Kohn-Sham eigenvalue of neutral VH3

      • Oxygen-vacancy pair (Si:A-centre) and its interaction with H
      • Phosphorus-vacancy pair (Si:E-centre)
      • Germanium-vacancy pair
        (Apparently Ge can lock single vacancies. If you assume that this pair is still very vacancy-like, GeSi:V should exhibit similar deep levels to those of the isolated single vacancy...)
      • Tin-vacancy pair
      • Interaction of atomic hydrogen with the above: partially H-passivated V2, E- and A-centres.
The projects described above are being carried out in close collaboration with two experimental groups:
  • J. Weber (MPI, Stuttgart - Germany)
  • B. Bech Nielsen (IPA, Aarhus - Denmark)

AIMPRO - an acronym for Ab Initio Modelling PROgram - allows the study of structural, electrical and vibrational properties of defects in semiconductors. This is a self-consistent local density functional pseudopotential cluster method.

A few notes about the AIMPRO method...
Or the full monty:

The Ab Initio Cluster Method and the Dynamics of Defects in Semiconductors

By R. Jones and P. Briddon
(To appear in Identification of Defects in Semiconductors, Ed. M. Stavola and Semiconductors and Semimetals Treatise Eds. R. K. Willardson, A. C. Beer and E. R. Weber, Academic Press)