We present a detailed study of the morphology and composition of tungsten oxide (WO3) thin films, grown by radio frequency magnetron reactive sputtering at substrate temperatures varied from room temperature (RT) to 500 °C, using infrared (IR) absorption, Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS). This work includes valuable new far-IR results about structural changes in microcrystalline WO3. Both IR absorption and Raman techniques reveal an amorphous sample grown at RT and initial crystallization into monoclinic structures for samples grown at temperatures between 100 and 300 °C. The Raman spectra of the samples grown at high temperatures indicate, apart from the monoclinic structure, a strain effect, with a distribution revealed by confocal Raman mapping. XPS indicates that the film surface maintains the stoichiometry WOx, with a value of x slightly greater than 3 at RT due to oxygen contamination, which decreases with increasing temperature.

Ga-doped ZnO (ZnO:Ga) thin films were prepared by radio-frequency–magnetron sputtering on conventional glass substrates at room temperature. The structural, electrical, and optical properties of these films as a function of argon pressure and film thicknesses were studied. All the films crystallized with the hexagonal wurtzite structure. The x-ray diffraction studies show that the ZnO:Ga films are highly oriented with their crystallographic c-axis perpendicular to the substrate. We discuss a methodology of using a “standardized platform” for comparison of samples deposited at different pressures, which provides an insight into the defect–resistivity relationship of each sample with respect to their microstructure. After the first annealing, the electrical properties of the films are dependent on the atmosphere used during postdeposition annealing treatment. A resistivity of 2.5 × 10−3 Ω · cm was obtained after vacuum annealing, and the films became an insulator after air annealing. The reproducibility of this treatment was verified. The average transmittance of all ZnO:Ga thin films is more than 85% in the visible range.

A wet loading method was developed to produce nano-sized LiBH4 combined with nano-SiO2 templates. The multicomponent LiBH4/SiO2 material synthesized by the wet method has been found to dehydrogenate at much lower temperatures than the pure LiBH4, as well as LiBH4/SiO2 mixtures prepared by ball milling. For example, the onset of dehydrogenation was decreased to about 200 °C for a wet-treated LiBH4/SiO2 mixture with a mass ratio of 1:1, and the majority of the hydrogen could be released below 350 °C. The improved dehydrogenation of the wet-treated LiBH4/SiO2 mixtures can be attributed to the destabilization of SiO2, resulting in the formation of lithium metasilicate (Li2SiO3) upon heating, and the confinement of LiBH4 to form nanoscale particles.

Sub-10 nm monodispersed NaYF4:Eu/Ba nanocrystals were synthesized by a hydrothermal method. Under 396-nm excitation, in addition to the characteristic emissions of Eu3+ ions, an intense emission band originating from the d–f transition of the Eu2+ ions is also observed, indicating that Eu3+ and Eu2+ coexist in Eu/Ba-codoped NaYF4 nanocrystals. The dependence of the luminescence on the Ba2+ concentration was studied. Tunable photoluminescence of NaYF4:Eu nanocrystals was successfully achieved by codoping with Ba2+ ions. In addition, when the Ba/Ln ratio is 3:7 and 4:1, pure cubic Ba0.92Y2.15F8.29:Eu and tetragonal BaYF5:Eu nanocrystals were obtained, respectively.

In this paper, polycrystalline CuIn(SxSe1–x)2 thin films with tunable x and Eg (band gap) values were prepared by controlling the sulfurization temperature (T) of CuInSe2 thin films. X-ray diffraction indicated the CuIn(SxSe1–x)2 films exhibited a homogeneous chalcopyrite structure. When T increases from 150 to 500 °C, x increases from 0 to 1, and Eg increases from 0.96 to 1.43 eV. The relations between x and Eg and the sulfurization process of CuIn(SxSe1–x)2 thin films have been discussed. This work provides an easy and low-cost technique for preparing large area absorber layers of solar cell with tunable Eg.

Sn–Zn based alloys are promising as Pb-free solders, and Cu is commonly used in electronic products. Solidification and interfacial reactions of Sn–8.8wt%Zn, Sn–8.8wt%Zn–0.05wt%Co, and Sn–8.8wt%Zn–0.5wt%Co solders on Cu substrates are investigated. Two different masses of solders are used. The degrees of undercooling increase with increasing Co additions in the Sn–8.8wt%Zn alloys. The reaction products evolve with reaction time, and the timing of different reaction stages is influenced by both the minor Co alloying and the mass of solders. In the initial reaction stage, two reaction phases, γ-Cu5Zn8 and ε-CuZn5, are observed in the Sn–8.8wt%Zn/Cu and Sn–8.8wt%Zn-0.05wt%Co/Cu couples, and only the γ-Cu5Zn8 phase is found when the Co addition is up to 0.5 wt%. The reaction layers are thinner with higher Co alloying. The addition of Co into the Sn–Zn alloys consumes Zn, and this depletion of Zn in the Sn–Zn solders is the primary reason for the changes of reaction products and the thinner reaction layers.