CsI∶Tl余辉产生和抑制机理的第一性原理研究  

First-principles Studies on the Mechanisms of Afterglow Generation and Suppression of CsI∶Tl

作　　者：郭丽娜 蒋璧有 陈平[1] 田春回 牛德青 GUO Lina;JIANG Biyou;CHEN Ping;TIAN Chunhui;NIU Deqing(State Key Laboratory of Dynamic Testing Technology,School of Information and Communication Engineering,North University of China,Taiyuan,030051,CHN;School of Optoelectronic Science and Engineering,University of Electronic Science and Technology of China,Chengdu,610054,CHN;Intelligent Measurement and Control Division,China South Industries Group Co.,Ltd.,Mianyang,Sichuan,621000,CHN)

机构地区：[1]中北大学信息与通信工程学院,电子测试技术国家重点实验室,太原030051 [2]电子科技大学光电科学与工程学院,成都610000 [3]中国兵器装备集团自动化研究所有限公司智能测控事业部,四川绵阳621000

出　　处：《固体电子学研究与进展》2023年第5期386-391,共6页Research & Progress of SSE

基　　金：国家自然科学基金资助项目(62001429)。

摘　　要：CsI∶Tl晶体受其余辉特性的影响,限制了其在快速X射线成像领域的推广应用。为探索CsI∶Tl晶体的余辉产生机理和抑制方法,利用Material Studio软件建立了纯CsI晶体、CsI∶Tl晶体和CsI∶Tl,Eu晶体的超晶胞模型,基于密度泛函理论的第一性原理及广义梯度近似和超软赝势框架计算三个模型的总态密度和分态密度。结果表明,CsI∶Tl晶体发射余辉是由于Tl掺杂引入的浅杂质能级约束了少量电子跃迁过程,导致余辉光子的延迟发射。而Eu共掺杂将在CsI∶Tl晶体中引入更深的杂质能级,能够有效地清除受限于Tl引入的浅电子陷阱的电子,并防止电子受环境热扰动影响重新受激发射二次光子,从而有效抑制CsI∶Tl晶体中余辉光子发射。CsI∶Tl suffered from afterglow which limited its application in the field of high-speed X-ray imaging.In order to study the mechanism of afterglow generation and the method to suppress afterglow of CsI∶Tl,the supercell models of perfect CsI,CsI∶Tl and CsI∶Tl,Eu crystal were built by the software of Material Studio.The total and partial density of states of these three models were cal-culated using first-principles based on density functional within the framework of generalized gradient approximation and ultra-soft pseudo-potential.The results indicate that the generation of afterglow in CsI∶Tl is due to the shallow impurity energy levels introduced by Tl,which restricts the transition of few electrons.Moreover,co-doping CsI∶Tl with Eu will introduce deeper impurity energy levels,which can effectively scavenge the electrons trapped by the shallow impurity energy levels introduced by Tl and prevent electrons from being disturbed by ambient heat to produce secondary photons,thus suppressing the emission of afterglow photons in CsI∶Tl.

关 键 词：CsI∶Tl CsI∶Tl Eu 余辉抑制 第一性原理 

分 类 号：O734.3[理学—晶体学]