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Lasing characteristics of randomly assembled ZnS nanosheets are studied at room temperature. Under 266-nm optical excitation, sharp lasing peaks emitted at around 332 nm with a linewidth less than 0.4 nm are observed in all directions. In addition, the dependence of lasing threshold intensity with the excitation area is shown in good agreement with the random laser theory. Hence, it is verified that the lasing characteristics of randomly assembled ZnS nanosheets are attributed to coherent random lasing action. [ABSTRACT FROM AUTHOR]

We report a new route to synthesize nanosized (La0.67-XGdX)Sr0.33MnO3 (X=0.1,0.15) perovskite crystalline complex oxides at calcination temperatures of 600-900 °C using amorphous molecular alloy as precursor. The precursor could completely decompose into oxide at temperatures below 500 °C according to thermogravimetric analysis and differential thermal analysis results. X-ray diffraction demonstrated that the decomposed species was composed of perovskite structure at a calcination temperature of 600 °C for 2 h. The size and topography of the oxides are dependent on the calcination temperature of the precursor. The resulting particle size is in the range of 40-120 nm as determined by a transmission electron microscope. This method is effective and can be easily quantitatively controlled to synthesize nanosized perovskite complex oxides. The Curie temperature TC and the magnetocaloric effect of (La0.67-XGdX)Sr0.33MnO3 (X=0.1,0.15) nanoparticles are discussed based on the measurement of the low-field magnetization curve and the isothermal magnetization curve. [ABSTRACT FROM AUTHOR]

Nanocrystalline ZnS has been synthesized using a sonochemical reaction of a mixed solution of Zn(NO3)2, Na2S2O3 and (CH3)2(OH)CH in Ar under ambient conditions. Detailed investigations with X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) are reported. It was found that phase-pure ZnS nanocrystallites were produced, and the ZnS nanoparticles were about 6.5 nm in size, as indicated by TEM observation, The chemical mechanism for the formation of ZnS nanocrystals is discussed, This convenient method is found to he an efficient way to produce other chalcogenides as well. [ABSTRACT FROM AUTHOR]

This article describes both electrochemical deposition and electrophoretic deposition of high-density tellurium (Te) nanowire arrays with wire diameters of 60 nm and lengths of 15-20 µm in the nanochannels of anodic aluminum oxide (AAO) templates. The Te nanowires synthesized via electrochemical deposition (ECD) are generally single crystalline in nature with the wire longitudinal axis along the [001] direction, whereas those synthesized via electrophoretic deposition (EPD) show polycrystalline structures with numerous tiny Te crystallites packed randomly in the wires. The single-crystalline Te nanowires produced by the ECD route are believed to form under a near chemical equilibrium condition; however, the imposed transport and the rapid packing of Te nanocrystallites in the nanochannels of AAO template in external fields lead to polycrystalline Te nanowires in the EPD process. This comparative study of the Te nanowire formation in the nanochannels of AAO template will facilitate the tailoring of the growth of other inorganic nanowires of high quality. [ABSTRACT FROM AUTHOR]

Presents information on a study that achieved large-scale single-crystal cubic PbS nanorods using ultrasound irradiation in certain ethylenediamine acid solutions. Methodology of the study; Results and discussion on the study.

The photoluminescence (PL) of anodic alumina membranes with different pore sizes is investigated in this paper. We observe that a small pore size leads to a decrease of photoluminescence intensity, an increase of the recombination lifetime, and a broadening of the emission band. The origin of the PL characteristics are discussed together with the decay measurement of the emission band. [ABSTRACT FROM AUTHOR]

Large-scale synthesis of amorphous silica nanowires was achieved by using simple physical evaporation of a mixture of Si and Al2O3 powders. Scanning electron microscopy observations showed that the silica nanowires have lengths of several mm and diameters of 20-100 nm. X-ray photoelectron spectroscopy revealed that these nanowires consisted of Si and O elements in an atomic ratio of approximately 1:2, consistent with the stoichiometric formula SiO2. Photoluminescence measurements showed a blue luminescence band in the wavelength range of 400-500 nm with three peaks at 420 nm, 440 nm, and 470 nm, respectively, which also differs from the previous reports of the photoluminescence for oxygen-deficient silica nanowires. This may suggest that the fully oxidized silica nanowires still have many structural defects that contribute to the photoluminescence. [ABSTRACT FROM AUTHOR]

Nanoscale silicon powders of 10 nm scale have been prepared by laser-induced chemical vapor deposition. Diffuse reflectance spectra (DRS) of the silicon powder at different annealing temperatures have been measured. Both the maximum and the drop-edge in reflectivity have been found to shift toward a shorter wavelength with increasing annealing temperature below 700 °C. The observed shifts in the spectra are ascribed to the reduction of the silicon crystallite size by oxidation of the surface in an annealing process. [ABSTRACT FROM AUTHOR]