论文部分内容阅读
用坩埚下降法(Bridgman)生长出了Bi离子掺杂的CdWO4单晶.测定了晶体不同部位的吸收光谱、发射光谱和X射线电子能谱(XPS).Bi离子的掺入引起CdWO4晶体的吸收边从345nm红移到399nm.在311nm,373nm,808nm和980nm光的激发下,分别观测到中心波长为470nm,528nm,1078nm和较弱的1504nm四个不同发射带.Bi:CdWO4单晶的XPS谱分别与Bi2O3(Bi3+)和NaBiO3(Bi5+)样品的进行比较,推断Bi3+和Bi5+离子同时存在于CdWO4晶体中.可见光波段的470nm与528nm荧光发射起因于CdWO4晶体基质中WO66-与掺杂于晶格中Bi3+离子的发光;而1078nm的发射峰则起因于Bi5+离子的发光.XPS的分析结果与荧光强度的变化一致,沿着晶体生长方向,1078nm的荧光强度逐步变弱,Bi5+离子的含量逐步减少;而位于528nm处的荧光强度则逐步增强,Bi3+离子的含量逐步增多.
The Bi-doped CdWO4 single crystals were grown by the Bridgman method.The absorption spectra, emission spectra and X-ray photoelectron spectroscopy (XPS) of different parts of the crystals were measured.The incorporation of Bi ions caused the absorption of CdWO4 crystals Red shift from 345nm to 399nm.Under the excitation of 311nm, 373nm, 808nm and 980nm, four different emission bands with central wavelength of 470nm, 528nm, 1078nm and weaker 1504nm were respectively observed.The XPS spectra of Bi: CdWO4 single crystal Spectra were compared with those of Bi2O3 (Bi3 +) and NaBiO3 (Bi5 +) respectively, and it was inferred that both Bi3 + and Bi5 + ions were present in CdWO4 crystals. Fluorescence emission at 470nm and 528nm in visible light band was caused by the formation of WO66- and doping While the emission peak of 1078nm is attributed to the luminescence of Bi5 + ions. The analysis results of XPS are consistent with those of fluorescence intensity. The fluorescence intensity at 1078nm gradually weakened along the crystal growth direction, and the content of Bi5 + ions gradually While the fluorescence intensity at 528nm gradually increased and the content of Bi3 + ions gradually increased.