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Abstract: Shuttlelike yttrium hydroxide (Y(OH)3) microcrystals attached with microrods in the middle part were prepared for the first time via a facile solvothermal process in the absence of templates or surfactants. Yttrium oxide (Y2O3) with similar morphology was also prepared by calcining the as-prepared Y(OH)3 at 500°C for 4h. X-ray powder diffraction (XRD) results demonstrate that the as-prepared Y(OH)3 and Y2O3 are attributed to hexagonal phase and cubic phase, respectively. The length of the shuttles is about 15μm and the diameter is about 2μm. The attached rods have an average size of 3μm in length and 1μm in diameter. Furthermore, the surface of the rods and the shuttles is very smooth. The influences of solvent, concentrations of yttrium nitrate and sodium hydroxide on the morphologies of Y(OH)3 were investigated in detail. Y2O3:Eu3+ microstructures with similar morphology were also prepared and their photoluminescence (PL) properties were investigated. [Copyright &y& Elsevier]

Abstract: The bilayer InAs/In0.36Ga0.64As/GaAs(311B) quantum dots (QDs), including one InAs buried quantum dot (BQD) layer and the other InAs surface quantum dot (SQD) layer, have been grown by molecular beam epitaxy (MBE). The optical properties of these three samples have been studied by the piezoreflectance (PzR) spectroscopy. The PzR spectra do not exhibit only the optical transitions originated from the InAs BQDs, but the features originated from the InAs SQDs. After the InAs SQDs have been removed chemically, those optical transitions from InAs SQDs have been demonstrated clearly by investigating the PzR spectra of the residual InAs BQDs in these samples. The great redshift of these interband transitions of InAs SQDs has been well discussed. Due to the suitable InAs SQD sizes and the thickness of In0.36Ga0.64As layer, the interband transition of InAs SQDs has been shifted to ∼1.55μm at 77K. [Copyright &y& Elsevier]

Crystalline Si3N4/amorphous SiO2 nanocables have been synthesized from silicon substrates and N2 at 1250 °C without any catalyst. The morphology, composition profiles and photoluminescence of the nanocables have been studied. It has been demonstrated that an inner crystalline Si3N4 is formed whereas the outer SiO2 is amorphous. The nanocables are 90–110 nm in diameter and several micrometers in length, while the core-wires are 30–50 nm in diameter. Intense blue or near violet photoluminescence from these nanocables was observed. A tentative growth mechanism model for the crystalline Si3N4/amorphous SiO2 nanocables has been suggested and discussed. [Copyright &y& Elsevier]

Abstract: The optical properties of GaAsN films have been studied by photoluminescence (PL) and photo-modulation reflection (PR). The effects of postgrowth anneal on the band structure and optical efficiency have been shown basing on these measurements. Both the samples with close N content grown at different temperatures exhibit high crystalline quality according to the X-ray diffraction. The alloy films show remarkable stability against rapid thermal annealing (RTA) process. The blueshift of the PL peak energy is found to be 3.8meV when annealing up to 900°C, meanwhile the PL intensity increases significantly until RTA at 850°C. [Copyright &y& Elsevier]