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Flower-like Bi2S3 nanostructures consisting of nanorods with a lateral size of about 30 nm have been prepared via a thioglycolic acid (HSCH2COOH, TGA) assisted hydrothermal method. The x-ray diffraction (XRD) pattern shows that the obtained flower-like Bi2S3 nanostructures are of orthorhombic phase. High-resolution transmission electron microscopy (HRTEM) identifies that the flower-like Bi2S3 nanostructures are single crystalline in nature. It is believed that the sodium thiosulfate (STS) as the sulfur source could facilitate the formation of flower-like embryos and the TGA could enhance the anisotropic growth of Bi2S3 nanorods initiated from the embryos. STS and TGA play the key roles in the formation of flower-like Bi2S3 nanostructures during the hydrothermal process. [ABSTRACT FROM AUTHOR]

The influence of copper precipitation on oxygen precipitation in Czochralski-grown silicon was investigated by Fourier transform infrared spectroscopy, defect etching and transmission electron microscopy combined with energy dispersive x-ray analysis. It was found that interstitial copper almost had no influence on oxygen precipitation but copper precipitation remarkably enhanced oxygen precipitation. Furthermore, the enhancement of copper precipitation under air cooling (30 K s-1) on oxygen precipitation subsequently was much more noticeable than that of copper precipitation under slow cooling (0.3 K s-1). It was also observed that the dislocations induced by oxygen precipitates occurred in the samples without copper contamination, but in the samples experiencing copper precipitation, oxygen preferably precipitated on the dislocations induced by copper precipitates, or dislocation-free oxygen precipitates occurred. These results indicate that heterogeneous nucleation of oxygen precipitates on dislocations and successful release of the stress from oxygen precipitation are responsible for the enhancement of oxygen precipitation. [ABSTRACT FROM AUTHOR]