SURFACE PROPERTIES AND ELECTRONIC STRUCTURE OF FUNCTIONAL OXIDES
Our research is concerned with exploring the relationship between the surface properties and the electronic structure of functional metal oxides.
We are interested in two main classes of materials, both with applications in the field of solar energy conversion: transparent conducting oxides (TCOs); and oxides capable of inducing photocatalytic reaction such as the splitting of water into hydrogen and oxygen or the degradation of organic pollutants. Single crystal TCOs are grown in a ultrahigh vacuum (UHV) apparatus unique within the UK which uses atomic beams of metals and oxygen to prepare materials of the highest quality. The films fabricated in this way are characterised by a range of techniques including high resolution transmission electron microscopy, atomic force and scanning tunnelling microscopy, high resolution diffraction and transport measurements.
A range of electron spectroscopic techniques including hard and soft X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy are used to study electronic structure. We also collaborate with Professor Kevin Smith at the University of Boston in the measurement of X-ray absorption and emission spectra, which provide decisive evidence about details of the bonding in simple inorganic solids.
Extensive use is made of national and international synchrotron radiation facilities including Diamond (UK), the ESRF (Grenoble, France), ELETTRA (Trieste, Italy), MaxLab (Lund, Sweden), NSLS (Berkeley, USA) and NSLS (Brookhave, USA). We are also major users of the ultrahigh resolution XPS facility at the Daresbury Laboratory.
Underpinning the UHV growth studies we are also involved in more conventional solid state synthesis, with characterisation of the ceramic compounds by X-ray diffraction and magnetic susceptibility and conductivity measurements.
Indium oxide on cubic ZrO2 viewed by scanning electron microscopy (left) and atomically resolved high resolution transmission electron microscopy (right)