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Some peculiarities of straight and zig-zag grain boundaries in multi-crystalline Si ingots were analyzed by Scanning Electron Microscopy-Electron BackScatter Diffraction (SEM-EBSD) and Three Dimensional (3D) grain boundary reconstruction. In the cases where straight grain boundaries were perpendicular to facing {111} planes in the two neighboring grains, they were found parallel, within the measurement accuracy, to the bisector of the two facing {111} planes. This is in agreement with the theory predicting the existence of Facetted-Facetted grooves during the growth of multicrystalline Si. Another grain boundary was corresponding to the predicted Facetted-Rough groove. It was found that the zig-zag grain boundaries were successively composed of {111} twin planes and (...11)/(011) planes, so that the two grains are always in Σ3 relationship. The phenomenon leading to the formation mechanism for these boundaries remains a subject for research. [ABSTRACT FROM AUTHOR]

Abstract: Colloidal SnO2 nanocrystals are prepared via a solvothermal method using oleic acid as a stabilizing agent. Preferred orientation growth along [001] direction of colloidal SnO2 nanocrystals is observed, thereby pure SnO2 nanoparticles with quasi-sphere shape being converted to nanorods due to Gd3+ ions doping. In addition, with increasing Gd3+ doping concentration, the size of SnO2 nanorods decreases. The decrease in size and the change in the shape are ascribed to the increase in the growth rate along [001] direction due to the cationic doping with a surface charge modification. Our results demonstrate a simple method to tune the size and shape of SnO2 nanocrystals through cationic doping with Gd3+ ions. [Copyright &y& Elsevier]