| Origin of the 420 nm Absorption Band and Effect of Doping Fluorine in PbWO4 Crystals |
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| 作者姓名： | 陶琨 张启仁 刘廷禹 张飞武 |
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| 作者单位： | CollegeofScience,UniversityofShanghaiforScienceandTechnology,Shanghai200093 |
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| 摘 要： | The electronic structures for three types of PbW04 (PWO) crystals, the perfect PWO, the PWO containing lead vacancy (PWO-Vpb) and fluorine doped PWO crystal (F^-：PWO), are systematically studied within the framework of density functional theory. The computational results show that the Pb 6s state situates below the valence band so that Pb^2 ions are unable to trap holes forming Pb^3 or Pb^4 to compensate for VPb^2-. The hole-trappers in PWO-Vpb are O^2- ions. Two of the longer-bond O^2- ions share a hole forming O2^3-, and four of the longer-bond oxygen ions trap two holes forming an associated color centre [O2^3--Vpb-O2^3-], which may be the origin of the 42Onto absorption band. It is also concluded that the doping of F^- would reduce the band gap and F^- ions substituting for O^2- can effectively restrict the formation of [O2^3--Vpb-O2^3-] and weaken the 42Onm absorption band and hence enhance the scintillation property of PWO.
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| 关 键 词： | 吸收光谱带 掺氟效应 PbWO4晶体 电学结构 |
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