F,Y双掺钨酸铅晶体的发光性能和微观缺陷

The luminescence and defects of F,Y co-doped PbWO_4 crystals

通过透射光谱、光产额(LY)和光致发光等发光性能测试,研究了F,Y双掺钨酸铅(PbWO4,简称PWO)晶体的发光性能,并利用热释光曲线和正电子湮没寿命谱对F,Y双掺PWO晶体中的缺陷种类和变化进行了分析.结果表明:与未掺杂晶体相比,双掺样品在350nm附近的透过率大大提高,吸收边向短波方向移动约30nm,光致发光谱中出现位于350nm的发光峰,双掺样品的LY(100ns内)为未掺杂PWO的2·7倍左右.晶体中主要存在的缺陷为(WO3)-和(WO4)3-,对双掺晶体进行600℃真空气氛下退火发现:晶体中(WO3)-和(WO4)3-缺陷浓度增加;而600℃空气气氛下退火则有利于填补氧空位,并将(WO3)-和(WO4)3-氧化为正常的钨酸根阴离子基团,从而改善晶体的发光性能.这一实验结果对提高PWO晶体的LY提供了新的思路.

The influence of F, Y co-doping on the luminescence properties and defects of PbWO4 （PWO） have been investigated by correlated measurements of transmission spectra, light yield, photoluminescence spectra, thermoluminescence and positron annihilation lifetime. F doping results in a new luminescence band peaked around 350 nm, which gives a significant improvement in luminescence properties of PWO. Meanwhile, Y-dopant efficiently reduces trapping state and accelerates the scintillation decay process. Compared with the undoped PWO samples, the light yield （100 ns） of F, Y co-doped PWO crystal was increased bya factor of 2.7. The main defects （WO3）^- and （WO4）^3- in PWO crystals for lack of oxygen during growth were investigated. Thermoluminescence results show that the defects in PWO crystals increase when annealed in vacuum and these defects can be also suppressed by annealing in air at 600 ℃.