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ZnO thin film with strong orientation (0 0 2) and smooth surface morphology was electrosynthesized on ITO-coated glass substrate at room temperature under pulsed voltage. Photoluminescence (PL) shows two obvious peaks: violet band and strong green band. The former is due to the free-excitonic transition and the latter is believed to arise from the single ionized oxygen vacancy (V-O(+)). Raman scattering reveals that the 580 cm(-1) mode and the shoulder peak mode at 550 cm(-1) originate from the N-related local vibration mode (LVM) and E-1 (LO) mode, respectively. (c) 2005 Elsevier B.V. All rights reserved.

The saturated vapor adsorption (SVA) method is adopted to fabricate nanorods, nanotubes, and special nanostructures with the assistance of template. Here, germanium tubular structures with several diameters (50-200 nm) were produced with porous anodic alumina (PAA) template via SVA. The germanium tubular structures grew inside the nanopores, whose size agreed with that of Ge nanotubes, and then expanded to outside of PAA template, forming pipette-like structures. The Ge tubular structure growth process can be explained by both the vapor-solid and oxide-assisted growth mechanisms, which is different from the mechanism for nanorod growth. (c) 2005 Elsevier B.V. All rights reserved.

A large quantity of monocrystalline germanium nanorods and their arrays were produced on a porous anodic alumina (PAA) template utilizing saturated vapor adsorption, during which the Ge gas pressure was saturated at a high temperature in an airtight quartz tube. Raman scattering and photoluminescence (PL) results were acquired from the Ge nanorod array and discussed in details. Using Si-based PAA template with 25 nm nanopores, Si-based Ge nanorod array with a large area (larger than 1x1 cm(2)) was obtained and the quantum confinement effect is demonstrated in Raman spectrum. (C) 2005 American Institute of Physics.

We report on cathodoluminescence (CL) of monosized and well-aligned 4 angstrom single-walled carbon nanotubes in a zeolite template (AlPO4-5 single crystal). The CL exhibits three emission bands centered at 1.87, 2.22, and 2.98 eV, which are assigned to three possible 4 angstrom tube structures (4,2), (5,0), and (3,3), respectively. The assignation is based on first-principles calculations, Raman scattering measurement, and CL behavior of various samples. The emission peak shift of the (5, 0) tube is explained by the transition mechanism being different from photoluminescence due to the excitation of electrons with high energy. (c) 2005 American Institute of Physics.

We report on cathodoluminescence (CL) of monosized and well-aligned 4 angstrom single-walled carbon nanotubes in a zeolite template (AlPO4-5 single crystal). The CL exhibits three emission bands centered at 1.87, 2.22, and 2.98 eV, which are assigned to three possible 4 angstrom tube structures (4,2), (5,0), and (3,3), respectively. The assignation is based on first-principles calculations, Raman scattering measurement, and CL behavior of various samples. The emission peak shift of the (5, 0) tube is explained by the transition mechanism being different from photoluminescence due to the excitation of electrons with high energy. (c) 2005 American Institute of Physics.

Si-based nano-island arrays were fabricated on porous anodic alumina by two methods. In the first method, a thick silicon film was first deposited onto the surface with highly ordered bowl array prepared by anodizing an Al foil, followed by the formation of a polycrystalline silicon nano-island array on the surface close to the bowl array after dissolving aluminum. In the second method, porous anodization was performed on an Al thin film on Si and a SiO2 nano-island array was subsequently formed electrochemically. Time-resolved atomic force microscopy and photoluminescence were used to investigate the growth process as well as the mechanism of the growth process. Our proposed mechanism as well as assumptions made to formulate the model were found to be in agreement with the experimental results. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

High-quality (100) ZnO films with smooth surface topography have been synthesized on Si substrate by plasma immersion ion implantation. The materials exhibit compressive stress because of room temperature growth. After annealing at different temperatures, various visible photoluminescence bands are observed. The optical phenomenon as well as the transition mechanism which may involve defects such as [Zn-1], [V-Zn], and [O-i(-)] induced by the high substrate bias are discussed in this paper. (C) 2004 Elsevier Ltd. All rights reserved.