The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

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A comprehensive review of zno materials and devices

This review describes a new paradigm of electronics based on the spin degree of freedom of the electron. Either adding the spin degree of freedom to conventional charge-based electronic devices or using the spin alone has the potential advantages of nonvolatility, increased data processing speed, decreased electric power consumption, and increased integration densities compared with conventional semiconductor devices. To successfully incorporate spins into existing semiconductor technology, one has to resolve technical issues such as efficient injection, transport, control and manipulation, and detection of spin polarization as well as spin-polarized currents. Recent advances in new materials engineering hold the promise of realizing spintronic devices in the near future. We review the current state of the spin-based devices, efforts in new materials fabrication, issues in spin transport, and optical spin manipulation.

http://science.sciencemag.org/content/sci/294/5546/1488.full.pdf

Spintronics: a spin-based electronics vision for the future.

The surface science of titanium dioxide

Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

Understanding TiO2 photocatalysis: mechanisms and materials.

Photoinduced reactivity of titanium dioxide

Ferroelectric properties of multiphase Bi–Fe–O thin films

We have fabricated single crystal-like BiFeO3 (BFO) thin films by flux-mediated epitaxy using pulsed laser deposition (PLD). The Bi–Cu–O flux composition and its thickness were optimized using composition spread, thickness gradient, and temperature gradient libraries. The optimized BFO thin films grown with this technique showed larger grain size of ∼2μm and higher dielectric constant in the range of 260–340 than those for standard PLD grown films. In addition, the leakage current density of the films was reduced by two orders of magnitude compared to that of standard PLD grown films.

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Enhanced dielectric properties in single crystal-like BiFeO 3 thin films grown by flux-mediated epitaxy

A high-resolution transmission electron microscopy investigation of the microstructure of TiO2 anatase film deposited on LaAlO3 and SrTiO3 substrates by laser ablation

We report on multiphase thin film growth of the Bi-Mn-O system on SrTiO3 (100) substrates. By varying the deposition oxygen partial pressure, the dominant phase formed in the film can be continuously changed from single phase epitaxal multiferroic BiMnO3 to epitaxally grown ferromagnetic Mn3O4. X-ray diffraction and transmission electron microscopy revealed that epitaxial multiferroic nanocomposites consisting of BiMnO3 and Mn3O4 form when the deposition pressure is ≈10 mTorr. The magnetic properties of the films were found to change as a function deposition pressure in a manner consistent with the variation in the nanocomposite microstructure.

Multiphase growth in Bi-Mn-O thin films

As a treasure island of new functional materials, metal oxides attract rapidly growing interest as exemplified by the high- T c cuprates and quantum functional perovskites. The development of new efficient instrument to construct artificially designed crystal lattices and hetro-junctions is considered to facilitate the systematic exploration of new materials, properties, and application of oxides. Powerful tools for this purpose are designed based on combinatorial chemistry and molecular layer epitaxy. With focuses on the concept and method, this novel technology of combinatorial laser MBE is reported and demonstrated to be useful for high throughput synthesis of functional oxide thin films and layered lattices.

Makoto Murakami

Papers

Ferroelectric properties of multiphase Bi–Fe–O thin films

Enhanced dielectric properties in single crystal-like BiFeO 3 thin films grown by flux-mediated epitaxy

A high-resolution transmission electron microscopy investigation of the microstructure of TiO2 anatase film deposited on LaAlO3 and SrTiO3 substrates by laser ablation

Multiphase growth in Bi-Mn-O thin films

Concept and development of combinatorial laser MBE for oxide electronics