【摘要】 用缺陷化学方法讨论了Nd3+、Th4+、Sb5+掺杂PbWO4(PWO)中可能存在的杂质缺陷模型,用GULP软件计算了不同杂质缺陷的生成能.计算结果表明,Nd3+和Th4+将占据PWO晶体中VP2b-周围的Pb位,对VP2b-的电荷补偿抑制了PWO晶体中420 nm吸收带.Sb5+在高浓度掺杂时将占据PWO晶体中V2O+周围的W位,并由于占据W位所呈现的一价负电性补偿V2O+的正电性,使孤立的铅空位增多,引起350 nm吸收的减弱和420 nm吸收的增强.更多还原

【Abstract】 The positions of the impurity ions of Nd3+,Th4+,Sb5+ in PbWO4(PWO) crystal are simulated by computer technology.The corresponding defect clusters energy is calculated.The defect chemistry and the formation of the defect clusters are discussed.The mechanism of the doping effects of Nd3+,Th4+,Sb5+ are studied.The calculation results show that the Nd3+ and Th4+ would occupy the Pb sites near V2-Pb,and restrict the 420 nm absorption band by compensating the electronegative charges of V2-Pb.When the PWO is doped with high concentration,the Sb5+ would occupy the W sites near V2+O,make the V2-Pb capture two holes more easily to form the colour center of 420 nm absorption.The conclusions are detailedly discussed.更多还原