SrS∶Eu,Sm光存储机理的研究

采用高温固相反应法在还原气氛下制备了SrS:Eu,Sm样品,利用荧光光谱仪测量了这种光存储材料的激发光谱和发射光谱.将样品用紫外灯(265 nm)照射激发饱和后,再用980 nm的红外激光器激励,利用荧光光谱仪测试得到了峰值位于599 nm的光激励发光光谱.此外还利用热释光谱仪测试了样品的热释光谱.探讨了SrS:Eu,Sm的光存储机理,认为引入的稀土离子在SrS的带隙中形成分裂能级.当用紫外光照射材料时,Eu的电子从基态被激发到激发态或基质材料的导带,其中一部分电子被辅助激活剂Sm的陷阱俘获,实现信息写入.当材料被与陷阱深度相当的红外光激励时,电子陷阱Sm2 俘获的电子才可能跃出俘获能级,与空穴在Eu的激发态和基态能级上复合,多余的能量以可见光的形式释放出来,实现信息读出.

Optical Storage Mechanism of SrS: Eu, Sm

The SrS∶Eu, Sm powder was prepared by high temperature solid state reaction method in reducing atmosphere. Its emission spectrum and excitation spectrum were measured by fluorescence spectrophotometer. The sample was stimulated by a 980 nm infrared laser after exposing to ultraviolet lamp(265 nm). The peak value of the photostimulated spectrum was located at 599 nm. Thermal spectrum was measured by thermal spectrophotometer. Optical storage mechanism of SrS∶Eu, Sm was discussed. It was thought that rare earth ions form splitted energy level in the forbidden band of SrS. When the sample was exposed in ultraviolet lamp, the electrons of Eu were excited from ground state to excited state or conduction band. The part of these electrons was trapped by Sm and information writing was realized. If the sample was stimulated by infrared which corresponded to the depth of trap, the electrons trapped by Sm were released and recombined with holes in the excited state or ground state of Eu. The extra energy was released with visible light and information reading was realized.