高分辨X射线衍射研究杂质对晶体结构完整性的影响

用水溶液生长晶体的方法生长出了不同掺杂的Sr(NO₃)₂晶体.用电子探针研究了杂质在晶体中的分布情况.结果表明,杂质在晶体中存在扇形分凝,其中Ba在{100}扇形区的含量大于{111}扇形区,而Pb的分凝情况相反,在{111}扇形区的含量大于{100}扇形区.用高分辨X射线衍射摇摆曲线技术研究了纯的、掺Ba的和掺Pb的Sr(NO₃)₂晶体的完整性情况,并用X射线衍射动力学理论计算了完整Sr(NO₃ 关键词： 高分辨X射线衍射 杂质 水溶液晶体生长

STUDIES OF THE IMPURITY EFFECTS ON CRYSTALLINE QUALITY BY HIGH-RESOLUTION X-RAY DIFFRACTION

Sr(NO 3) 2 single crystals with different impurities doped were grown from aqueous solutions. The distribution of impurities in Sr(NO 3) 2 crystals were investigated by electron probe micoranalysis. Results show that the distribution of impurities illustrates a compositional zoning behaviour. The Ba 2 has a higher concentration in the {100} growth sectors than in the {111} sectors. On the contrary, Pb 2 has a higher concentration in {111} growth sectors than in {100} sectors. The crystalline perfection of the pure and Ba 2 or Pb 2 doped Sr(NO 3) 2 crystals was studied by high-resolution X-ray rocking curve technique. The high-resolution X-ray rocking curve of the ideal Sr(NO 3) 2 crystal was theoretically calculated based on the dynamical X-ray diffraction theory. High-resolution X-ray diffraction results show that the crystalline quality in the growth sectors of the pure Sr(NO 3) 2 crystal is fairly high, since its experimental rocking curve is very close to the theoretical calculation. However, in the areas of the sector boundary the full width at half maximum of the rocking curve gets broader due to the lattice stress in the boundary area. The doping of impurities will deteriorate the quality of the crystal and induce an inhomogeneity behaviour of the crystalline quality. As for the Ba 2 doped Sr(NO 3) 2 crystal, the crystalline quality in {111} growth sectors is higher than that in {100} sectors. On the contrary, the crystalline quality in {100} growth sectors is higher than that in {111} sectors for Pb 2 doped Sr(NO 3) 2 crystal. This coincides well with the composition distributions of the dopants.