Showing papers by "Yue Wu published in 2002"
TL;DR: The influence of ingot purity as well as B2O3 fluxing on the crystallization of undercooled Pd43Ni10Cu27P20 is studied in a differential scanning calorimeter as discussed by the authors.
Abstract: The influence of ingot purity as well as B2O3 fluxing on the crystallization of undercooled Pd43Ni10Cu27P20 is studied in a differential scanning calorimeter. B2O3 fluxing strongly influences the isothermal crystallization behaviour at temperatures above the nose in the time-temperature-transformation diagram. The ingot purity, in contrast, affects the isothermal crystallization at low temperatures but leaves the crystallization at high temperatures relatively unaltered. Thermal analysis, together with microstructure investigations of samples processed and prepared under different conditions, suggests two sources of heterogeneous nucleation. One source is surface impurities, which can be passivated by fluxing with B2O3. The other consists of impurities from the ingot materials homogeneously distributed within the sample. Crystallization at high temperatures is controlled by the formation of one nucleus, preferentially formed at the surface, which can be suppressed to a large extent by B2O3 fluxin...
31 citations
TL;DR: In this paper, a large redshift of the photoluminescence peak energy is found in hydrogenated amorphous silicon films prepared by hot-wire chemical-vapor deposition with a high growth rate ⩾50 A/s.
Abstract: A large redshift of the photoluminescence (PL) peak energy is found in hydrogenated amorphous silicon films prepared by hot-wire chemical-vapor deposition with a high-growth rate ⩾50 A/s. The PL intensity is as high as that in the standard film and its temperature dependence shows thermalization behavior. The origin of the redshift is clarified by employing 1H nuclear magnetic resonance and mass density measurements. A ∼2% volume fraction of tube-like nanoscale voids is identified. The long spin-lattice relaxation time of H2 in the nanovoids implies a negligible density of silicon dangling bonds on the nanovoid surfaces. We suggest that highly strained bonds on these surfaces form broad conduction-band tail states that are responsible for the PL redshift.
14 citations