LiBaF_3:Eu^(2+)真空紫外光谱研究  

Vacuum Ultra-violet Spectra of LiBaF_3:Eu^(2+)

作　　者：周映雪[1] 张新夷[2] 汪东升[3] 张国斌[3] 

机构地区：[1]复旦大学应用表面物理国家重点实验室 [2]复旦大学同步辐射研究中心 [3]中国科学技术大学国家同步辐射实验室,合肥230029

出　　处：《发光学报》2002年第4期393-395,共3页Chinese Journal of Luminescence

基　　金：国家自然科学基金资助项目(59372093)

摘　　要：在室温下,二价稀土离子铕掺杂的LiBaF_3:Eu^(2+)粉末样品中,Eu2+的发射呈现双峰结构,有一峰值波长约为410nm的宽峰,对应于Eu2+的5d-4f跃迁,以及另一峰值波长约为360nm的窄峰,对应于Eu2+的4f-4f跃迁。在50～400nm波长范围,测量了样品的反射光谱,并利用Kramers-Kronig关系,计算了吸收光谱。从吸收光谱中,可以看到在102nm处有明显的吸收边,得到LiBaF3材料的禁带宽度Eg约为12.1eV。在高能端有53.4,59.4,65.3,69.2和76.5nm的吸收峰,它们对应于Ba2+的5p电子和F的2p电子芯能级之间的跃迁。在低能量的183.4nm处,有很明显的吸收峰,推测这对应于本征缺陷的吸收。更低能量的吸收峰,则对应于禁带中的一些杂质能级。在未经紫外光或X射线辐照之前,用长波长（>450nm）光激发LiBaF3:Eu2+粉末样品,可以观测到Eu2+离子的360nm和410nm发光,亦表现出光激励发光特性。At room temperature, there are two emission peaks in the luminescence spectrum of LiBaF3: Eu2+ powder sample. One is a broad band peaked at 410nm, and the other one is a narrow band peaked at 360nm, corresponding to 5d-4f and 4f-4f transitions of Eu2+, respectively. Furthermore, taking the reflection spectrum of Au thin film as reference, the reflection spectra of LiBaF3: Eu2+ sample are measured in the range of 50-400nm at U10B station of the National Synchrotron Radiation Laboratory (NSRL). The absorption spectra are calculated from the reflection spectrum by using the Kramers-Kronig relation. It is found that the energy gap Eg of this material is about 12.1eV. We believe that in the absorption spectra of LiBaF3:Eu2+, the 53.4, 59.4, 65.3, 69.2 and 76.5nm sub-bands correspond to transitions between core levels of Ba2+ 5p and F-2p electrons, respectively. Then the 183.4nm sub-band is attributed to the intrinsic defects absorption.On the other hand, without the pre-irradiation, one can observe the luminescence of LiBaF3: Eu2+ powder sample under the excitation of wavelength longer than 450nm. It means that the LiBaF3:Eu2+ sample has the photo-stimulated character.

关 键 词：真空紫外光谱 光激励发光 同步辐射 LiBaF3:Eu^2+ 铕掺杂 钙钛矿型复合氟化物 固体可调谐激光器 发光特性 激光材料 

分 类 号：TN244[电子电信—物理电子学] O613.41[理学—无机化学]