Room-temperature electrosynthesized ZnO thin film with strong (002) orientation and its optical properties

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

Polycrystalline tubular nanostructures of germanium

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

Current transport studies of ZnO/p-Si heterostructures grown by plasma immersion ion implantation and deposition

Rectifying undoped and nitrogen-doped ZnOp-Si heterojunctions were fabricated by plasma immersion ion implantation and deposition. The undoped and nitrogen-doped ZnO films were n type (n∼ 1019 cm-3) and highly resistive (resistivity ∼ 105 Ω cm), respectively. While forward biasing the undoped- ZnOp-Si, the current follows Ohmic behavior if the applied bias Vforward is larger than ∼0.4 V. However, for the nitrogen-doped- ZnOp-Si sample, the current is Ohmic for Vforward 2.5 V. The transport properties of the undoped- ZnOp-Si and the N-doped- ZnOp-Si diodes were explained in terms of the Anderson model and the space charge limited current model, respectively. © 2006 American Institute of Physics.link_to_subscribed_fulltex

Synthesis and optical properties of germanium nanorod array fabricated on porous anodic alumina and Si-based templates

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

Growth and visible photoluminescence of highly oriented (100) zinc oxide film synthesized on silicon by plasma immersion ion implantation

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

Visible cathodoluminescence of 4 A angstrom single-walled carbon nanotubes

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

Change of the

For the electron capture of 7Be in the metallic environments Pd and In the 7Be half-life was observed to increase by 0.9±0.2 and 0.7±0.2%, respectively, while in the insulator Li2O it was unchanged within experimental error (all samples cooled to T = 12K). The observations are consistent with the predictions of the Debye plasma model applied to the quasi-free electrons in the metals