ScienceDirect.com - Materials Science in Semiconductor Processing - Effect of annealing on structural, optical and electrical properties of pulse electrodeposited tin sulfide films:
Polycrystalline tin sulfide (SnS) thin films were grown on conducting glass substrates by pulse electrodeposition. The effect of annealing on the physical properties such as structure, morphology, optical, and opto-electronic properties were evaluated to understand the effect of post-deposition treatment for SnS films. Annealing at temperatures higher than 250 °°C resulted in the formation of SnS2 as a second phase, however, no significant grain growth or morphological changes were observed for films after annealing at 350 °C. A small change in band gap of 0.1 eV observed for films annealed at 350 °C was interpreted as due to the formation of SnS2 rather than due to morphological changes. This interpretation was supported by X-ray diffractometry, scanning electron microscopy, and Raman spectral data. The electric conduction in the films is controlled by three shallow trap levels with activation energies 0.1, 0.05, and 0.03 eV. The trap with energy 0.03 eV disappeared after annealing at higher temperature, however, the other two traps were unaffected by annealing.
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Friday, November 30, 2012
ScienceDirect.com - Materials Science in Semiconductor Processing - Controlling the diameter of silicon nanowires grown using a tin catalyst
Materials Science in Semiconductor Processing - Controlling the diameter of silicon nanowires grown using a tin catalyst:
Silicon nanowires were grown on ITO-coated glass substrates via a pulsed plasma enhanced chemical vapor deposition method, using tin as a catalyst. The thin films of catalyst, with different thicknesses in the range 10–100 nm, were deposited on the substrates by a thermal evaporation method. The effect of the thickness of the thin film catalyst on the morphology of the silicon nanowires was investigated. The scanning/transmission electron microscopy images showed that the wire diameter increased as the thickness of the thin film catalyst increased. The nanowires grown using a thin film thickness of 10 nm were inhomogeneous in diameter, whereas the other thicknesses led to an increase in the homogeneity of the diameters of the nanowires. The dominant wire diameter of the grown silicon nanowires ranged from 70 to 80 nm with 10 nm catalyst thin film thickness, and increased to a range of 190–200 nm with 100 nm catalyst thin film thickness.
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Silicon nanowires were grown on ITO-coated glass substrates via a pulsed plasma enhanced chemical vapor deposition method, using tin as a catalyst. The thin films of catalyst, with different thicknesses in the range 10–100 nm, were deposited on the substrates by a thermal evaporation method. The effect of the thickness of the thin film catalyst on the morphology of the silicon nanowires was investigated. The scanning/transmission electron microscopy images showed that the wire diameter increased as the thickness of the thin film catalyst increased. The nanowires grown using a thin film thickness of 10 nm were inhomogeneous in diameter, whereas the other thicknesses led to an increase in the homogeneity of the diameters of the nanowires. The dominant wire diameter of the grown silicon nanowires ranged from 70 to 80 nm with 10 nm catalyst thin film thickness, and increased to a range of 190–200 nm with 100 nm catalyst thin film thickness.
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ScienceDirect.com - Materials Science and Engineering: B - The fabrication of SnSe/Ag nanoparticles on TiO2 nanotubes
ScienceDirect.com - Materials Science and Engineering: B - The fabrication of SnSe/Ag nanoparticles on TiO2 nanotubes:
SnSe and silver (Ag) nanoparticles were sequentially deposited on TiO2 nanotube (NT) by pulsed electrochemical deposition and polyol chemistry process, respectively. The morphological observation under scanning electron microscope (SEM) showed that the average size of SnSe was about 30 nm and the Ag was about 5 nm. Transmission electron microscopy (TEM) combined with selected area electron diffraction (SAED) examination indicated that Ag nanoparticles exhibited a well-defined crystallinity. However, SnSe nanoparticles were amorphous and they turned to crystalline after being annealed at 300 °C in the atmosphere. The photocatalytic behavior of SnSe/Ag-TiO2 NT was evaluated by UV–vis diffuse reflectance spectra (DRS). The results showed that the deposition of SnSe and Ag nanoparticles increased light absorption intensity in the wavelength range of visible light, which implied that the SnSe/Ag-TiO2 NT is a promising ternary hybrid material in photocatalysis.
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SnSe and silver (Ag) nanoparticles were sequentially deposited on TiO2 nanotube (NT) by pulsed electrochemical deposition and polyol chemistry process, respectively. The morphological observation under scanning electron microscope (SEM) showed that the average size of SnSe was about 30 nm and the Ag was about 5 nm. Transmission electron microscopy (TEM) combined with selected area electron diffraction (SAED) examination indicated that Ag nanoparticles exhibited a well-defined crystallinity. However, SnSe nanoparticles were amorphous and they turned to crystalline after being annealed at 300 °C in the atmosphere. The photocatalytic behavior of SnSe/Ag-TiO2 NT was evaluated by UV–vis diffuse reflectance spectra (DRS). The results showed that the deposition of SnSe and Ag nanoparticles increased light absorption intensity in the wavelength range of visible light, which implied that the SnSe/Ag-TiO2 NT is a promising ternary hybrid material in photocatalysis.
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