The surface science of titanium dioxide

Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid–vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by the solid–vapour phase technique and their corresponding growth mechanisms. The application of ZnO nanobelts as nanosensors, nanocantilevers, field effect transistors and nanoresonators is demonstrated.

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Zinc oxide nanostructures: growth, properties and applications

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

Surface Science Studies of the Photoactivation of TiO2New Photochemical Processes

S. Pillai would like to acknowledge the UNSW Faculty
of Engineering Research Scholarship. K.R. Catchpole
acknowledges the support of an Australian Research Council fellowship.

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Surface plasmon enhanced silicon solar cells

Summary Quasicrystals are a family of complex bi- and tri- metallic alloys having non-crystallographic symmetries and novel, physical and electronic properties. In this article we introduce these materials, describing their discovery and unusual structure. We discuss the advantages of using scanning tunnelling microscopy (STM) to study their surfaces, and we demonstrate the application of various image analysis techniques to extract quantitative information on their surface structure. Lastly we point out some current directions in research on these fascinating materials.

Imaging quasicrystal surfaces using scanning tunnelling microscopy

Surface Structure of Complex Metallic Alloys

Depth dependent order/disorder transitions in iron-rich thin films grown on i-Al–Pd–Mn studied by medium energy ion scattering

Molecular adsorption on both quasicrystalline and approximant substrates has produced a number of pseudomorphic films, and has led to a deeper understanding of the chemistry of the surfaces of these materials. Here, the recently reported reconstructed (111) surface of the 1/1 Au-Al-Tb Tsai-type approximant has been used as a template for pentacene (Pn) adsorption, which is investigated using scanning tunneling microscopy. This surface provides unique varieties of adsorption sites compared to a normal metal surface. After room-temperature deposition, the Pn molecules are mobile yet exhibit a structure which indicates a bond with the Tb atoms of the surface, while reflecting the twofold symmetrical nature of the reported Au/Al row reconstruction. Postdeposition annealing shows a linear arrangement of molecules in a specific adsorption geometry, likely corresponding to the most favorable energetic configuration.

Pentacene growth on the (111) surface of the 1/1 Au-Al-Tb approximant: Influence of surface geometry on adsorption

Photon stimulated ion desorption (PSID) surface EXAFS (SEXAFS) showed early promise, being successfully applied to the Mo(100)/0 system [1]. The technique offers a means to determine the coordination geometry of a substrate atom to which the desorbed adsorbate ion was bonded. Information regarding the adsorbate coordination geometry can also be obtained, although electron and fluorescence yield techniques can usually be used for this purpose if a majority surface species is the subject of interest. The surface specific nature of the PSID yield is unique amongst probes of the surface absorption coefficient. This conveys the possibility of using PSID SEXAFS to determine the coordination geometry about a substrate atom bonded to hydrogen or, for instance, the bond geometry of -OH on an oxide surface. In addition, the bond geometry of minority surface species can be probed, as in the Mo(100)/0 study. Clearly, PSID SEXAFS is potentially a very powerful tool in surface structure determination.

Ronan McGrath

Papers

Imaging quasicrystal surfaces using scanning tunnelling microscopy

Surface Structure of Complex Metallic Alloys

Depth dependent order/disorder transitions in iron-rich thin films grown on i-Al–Pd–Mn studied by medium energy ion scattering

Pentacene growth on the (111) surface of the 1/1 Au-Al-Tb approximant: Influence of surface geometry on adsorption

PSID SEXAFS Studies of Silicon Surface Chemistry