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In this paper, high-photosensitive CdS1- xSe x films are synthesized by a two-step technique, which includes the chemical bath deposition of CdS films and a following selenization process. The structural, optical, and photoelectric properties of the CdS1- xSe x films were investigated. With the substitution of selenium for sulfur atoms, grain sizes of the as-prepared CdS1- xSe x films are effectively enlarged and reach the scales of the films thickness when the selenization temperature exceeds 450 °C. With increasing the selenization temperature from 350 to 550 °C, the band gaps of CdS1- xSe x films gradually decrease from 2.37 to 1.82 eV. Under the co-action of the grain-size enlargement and band-gap decrease, the CdS1- xSe x films fabricated at 450 °C show very pronounced photosensitivity. Noteworthy, the ratio of photo to dark conductivity of the CdS1- xSe x film selenized at 450 °C reaches 1.1 × 105, suggesting a promising application potential in the photoelectric devices. [ABSTRACT FROM AUTHOR]

In this work, rapid thermal annealing (RTA) was employed to crystallize the amorphous silicon films deposited by hot-wire chemical vapor deposition. The influence of annealing temperature on structural and electrical properties was studied by Raman spectroscopy, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and temperature-dependent conductivity measurement. The results show that the amorphous silicon films can be successfully crystallized by RTA in a very short time. The crystallinity and electrical properties of the poly-Si films was greatly improved as the RTA temperature increasing. When the temperature higher than 900 °C, the poly-Si films obtained the crystalline fraction above 95 %, and the hydrogen atoms almost disappeared in the poly-Si films. At the temperature of 1,100 °C, polycrystalline silicon films with conductivity of 16.4 S cm is obtained, which is seven orders in magnitude higher than that of the film annealed at 700 °C. [ABSTRACT FROM AUTHOR]

Microcrystalline silicon films (μc-Si:H) were deposited on stainless steel substrates by bias-assisted hot-wire chemical vapor deposition. The effect of substrate bias and substrate temperature on the crystallinity of μc-Si:H films was studied by Raman spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that both the Raman peak position and the crystalline fraction of the μc-Si:H films deposited at 200 °C were obviously improved by introducing −800 V substrate bias. The films deposited at 200 °C with −800 V substrate bias show strongly sharpened Si (111) peak together with Si (220) and Si (311) peaks, which was different from a weak Si (111) peak for those deposited without substrate bias. By increasing the substrate temperature from 200 to 300 °C, while keeping the substrate bias at −800 V, the crystallinity of the silicon films was further improved, and μc-Si:H films with crystalline fraction of 74 % was obtained. [ABSTRACT FROM AUTHOR]

Abstract: The influence of 4d transition-metal Nb substitution for Ni in Mn50Ni50−y Sn y (y =9, 10) alloys on the phase transitions and magnetocaloric effect was investigated. Austenitic phase of Nb-doped Mn50Ni50−y Sn y alloys have the cubic structure, and Nb addition results in the expansion of cell volume. The martensitic transformation temperatures decrease with the increase of Nb content, which could be explained by the decrease of valence electron concentration. Our results indicate that 4d transition-metal doping may provide an alternative way to tailor the martensitic transformation and the magnetocaloric effect in ferromagnetic shape memory alloys. [Copyright &y& Elsevier]

Abstract: Monoclinic Li3V2(PO4)3 can be rapidly synthesized at 750°C for 5min (MW5m) by using temperature-controlled microwave solid-state synthesis method (TCMS). The carbon-free sample MW5m presents well electrochemical properties. In the cut-off voltage 3.0–4.3, MW5m presents a charge capacity 132mAhg−1, almost equivalent to the reversible cycling of two lithium ions per Li3V2(PO4)3 formula unit (133mAhg−1), and discharge capacity 126.4mAhg−1. In the cut-off voltage 3.0–4.8V, MW5m shows an initial discharge capacity of 183.4mAhg−1, near to the theoretical discharge capacity. In the cycle performance, the capacity fade of Li3V2(PO4)3 is dependent on the cut-off voltage and the preparation method. [Copyright &y& Elsevier]

Abstract: To investigate the crystal structure and electrochemical performance of samples synthesized under different microwave solid-state synthesis condition, a series of Li3V2(PO4)3 samples has been synthesized at five different temperatures for 3–5min and at 750°C for various time. The as-synthesized Li3V2(PO4)3 samples are characterized and studied by ICP-AES analysis, X-ray diffraction (XRD), Rietveld analysis, scanning and transmission electron microcopy (SEM and TEM). At relatively lower temperature (650°C) and very short reaction time (3min), pure phase of Li3V2(PO4)3 could be synthesized in microwave irradiation field. The crystal structure and Li atomic fractional coordinate present a significant deviation upon the change of microwave irradiation temperature and time. Relatively, the diffusion ability of lithium cations and the electrochemical performance are affected. Under the proper reaction temperature and time, the carbon-free samples MW750C5m and MW850C3m show the best specific discharge capacity 126.4 and 132mAhg−1 at the voltage range of 3.0–4.3V, near the reversible cycling of two lithium ions per Li3V2(PO4)3 formula unit (133mAhg−1). At the voltage range of 3–4.8V, the sample MW750C5m presents the best initial specific charge capacity of 197mAhg−1, equivalent to the reversible cycling of three lithium ions per Li3V2(PO4)3 formula unit (197mAhg−1). The initial discharge capacity, the samples MW750C5m and MW850C3m present high specific discharge capacity 183.4 and 175.7mAhg−1, respectively. The relationship among microwave irradiation condition, crystal structure, lithium atomic fractional coordinates and the electrochemical performance have been discussed in detail. [Copyright &y& Elsevier]