【摘要】 根据钨酸铅晶体 (PbWO4,简称PWO)的缺陷化学和晶体结构特点 ,用光吸收谱、广延X射线吸收精细结构 (EX AFS)和精密X射线衍射 (XRD)方法对高温退火后PWO晶体进行微结构研究 ,获得了其退火前后缺陷变化的情况 ,据此提出生成态 (as grown)晶体中 35 0nm本征色心吸收带起源于V-F 空穴心 ,并指出PWO中紫外区色心吸收带的强度取决于晶体中铅空位和氧空位浓度之差 :[VPb]- [VO];然后 ,结合晶体在紫外光 (UV)辐照过程中色心的转化规律和偏振吸收谱的实验结果 ,提高 42 0nm辐照诱导色心吸收带起源于V0F 双空穴心 .并对所提出的PWO晶体色心模型的合理性进行了讨论 .更多还原

【Abstract】 Based on the defect chemistry and crystal structures of PbWO 4 (PWO) crystal,the microstructure of PWO crystal after high-temperature annealing was studied by optical absorption spectra,extended X-ray absorption fine structure (EXAFS) and refined X-ray diffraction (XRD) technigues.The variation of defect concentration before and after annealing has been observed.Accordingly,we proposed that the origin of the intrinsic 350nm absorption band in as-grown crystals was ascribed to the V - F hole centers.The intensity of the absorption band of colour centers in the ultraviolet region was found to be dependent on the concentration difference of the Pb and O vacancies:[V Pb]-[V O].Also,we suggested that the 420nm absorption band originates from the V 0 F dihole centers,based on the experimental results of formation of radiation-induced colour centers and their polarized absorption spectra.The feasibility of the proposed model of colour centers was also discussed.更多还原