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.

/pdf/surface-plasmon-enhanced-silicon-solar-cells-3duyubxz7i.pdf

Surface plasmon enhanced silicon solar cells

STM and SPA-LEED studies of O-induced structures on Rh(100) surfaces

Bravais' rule, of wide validity for crystals, states that their surfaces correspond to the densest planes of atoms in the bulk. Comparing a theoretical model of icosahedral Al-Pd-Mn with experimental results on sputter-annealed surfaces, we find that this correspondence breaks down, i.e., the surfaces parallel to the densest planes in the model are not necessarily the most stable bulk terminations. The correspondence is restored by recognizing that there is a contribution to the surface not just from a single geometrical plane but from a layer of stacked atoms, possibly containing more than one plane. We find that not only does the stability of high-symmetry surfaces match the density of the corresponding layerlike bulk terminations but the exact spacings between surface terraces can be determined and the typical area of the terraces can be estimated by a simple analysis of the density of layers predicted by the bulk geometric model.

/pdf/maximum-density-rule-for-bulk-terminations-of-quasicrystals-iovfymdeki.pdf

Maximum density rule for bulk terminations of quasicrystals

Scanning tunneling microscopy has been used to study the formation of a Bi monolayer deposited on the fivefold surface of $i{\text{-Al}}_{70}{\text{Pd}}_{21}{\text{Mn}}_{9}$. Upon deposition of low submonolayer coverages, the nucleation of pentagonal clusters of Bi adatoms of edge length $4.9\text{ }\text{\AA{}}$ is observed. The clusters have a common orientation leading to a film with fivefold symmetry. By inspection of images where both the underlying surface and the Bi atoms are resolved, the pentagonal clusters are proposed to nucleate on pseudo-Mackay clusters truncated such that a Mn atom lies centrally in the surface plane. The density of these sites is sufficient to form a quasiperiodic framework, and subsequent adsorption of Bi atoms ultimately leads to the formation of a quasicrystalline monolayer. The suggested nucleation site is different from that proposed on the basis of recent density-functional theory calculations.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1068&context=ameslab_pubs

Nucleation and growth of a quasicrystalline monolayer : Bi adsorption on the fivefold surface of i-Al70Pd21Mn9

Structural study of the five-fold surface of the Al70Pd21Mn9 quasicrystal

Quasicrystals are materials with long-range ordering but no periodicity. We report scanning tunneling microscopy (STM) observations of quasicrystalline molecular layers on 5-fold quasicrystal surfaces. The molecules adopt positions and orientations on the surface consistent with the quasicrystalline ordering of the substrate. Carbon-60 adsorbs atop sufficiently separated Fe atoms on icosahedral Al–Cu–Fe to form a unique quasicrystalline lattice, whereas further C60 molecules decorate remaining surface Fe atoms in a quasi-degenerate fashion. Pentacene (Pn) adsorbs at 10-fold symmetric points around surface-bisected rhombic triacontahedral clusters in icosahedral Ag–In–Yb. These systems constitute the first demonstrations of quasicrystalline molecular ordering on a template.

/pdf/templated-quasicrystalline-molecular-ordering-162s9d1x13.pdf

Ronan McGrath

Papers

STM and SPA-LEED studies of O-induced structures on Rh(100) surfaces

Maximum density rule for bulk terminations of quasicrystals

Nucleation and growth of a quasicrystalline monolayer : Bi adsorption on the fivefold surface of i-Al70Pd21Mn9

Structural study of the five-fold surface of the Al70Pd21Mn9 quasicrystal

Templated Quasicrystalline Molecular Ordering