Research On Electron Trapping Optical Storage Materials Synthesized By Microwave Sintering

Recently, with the rapid development of laser and optical storage technology, the study of rare earth doped sulfide electron trapping type optical storage materials was paid much more attention. As a novel type optical storage material, electron trapping type optical storage material can be used in both optical storage and infrared up-conversion. As optical storage materials, they possess comprehensive application values in super high density and velocity optical disk storage, image storage, information processing, optical calculation, and so on. As infrared up-conversion materials, they possess the merits of broader responding range among infrared band and lower responding threshold, and they have important application values in many fields, such as infrared detection, infrared up-conversion image and radiation dose detection. The microwave sintering method appeared in recent years is a novel method in solidstate materials synthesis. By using this method, the materials synthesized have several characteristics, such as modified structures and properties, the little red shift in fluorescence spectra, the high concentration of the doped ions, the fine sizes of the particles, the uniform distribution of the particle sizes, the small heat inertia, the selectivity of the heating mode and the rapid heating velocity, and so on.In this paper, electron trapping optical storage materials of three different substrates(CaS, SrS, CaSrS) were synthesized by microwave sintering method. The structures and properties of samples were studied by using XRD, SEM, fluorescence spectrometer, thermo-luminescence spectrometer. The influences of the output power of the microwave, the sintering times, the kinds and contents of rare earth, the contents of fluxes and the sulfur powder on the luminescent properties of the samples were also studied.The structures of CaS, SrS and CaSrS doped with different rare earth ions belong to the face-centered cubic structure, and their crystal lattice constants were 5.694A|°, 6.007 A and 5.853 A respectively. The excitation spectra of the samples are between UV and IR band, indicating that the samples can be excited by both ultraviolet light and infrared light. The emission spectra are mainly composed of three narrow bands emission of Sm³⁺. The photo-stimulated emission spectra excited by infrared light are broadband spectra peaking at 635nm, 595nm and 619nm respectively, which resulted from the transition of Eu²⁺. All the samples decay fast. The peak of the thermo-luminescence spectrum of CaS: Eu, Sm is at 420 ℃ . But no thermo-luminescence peak was found among the measuring range (20 - 500 ℃) of the instrument on the cases of SrS: Eu, Sm and CaSrS: Eu, Sm.