tailieunhanh - Dopant effect of Y on optical properties of ZnWO4 ceramics

This indicates that the Ce ion has an effect on the structure of ZnWO4 and suggests a solubility limit of Ce in ZnWO4 ceramics. In addition, we also calculated the Raman active modes by using group theory and we received 18 modes in Raman active and 16 modes in IR active. The absorption measurement indicates the band gap of ZnWO4 decreases with increasing Y content. The reasons for the above changes are discussed in this presentation. | JOURNAL OF SCIENCE OF HNUE Interdisciplinary Science 2013 Vol. 58 No. 5 pp. 17-21 This paper is available online at http DOPANT EFFECT OF Y ON OPTICAL PROPERTIES OF ZnWO4 CERAMICS Nguyen Manh An Faculty of Physics Hong Duc University Abstract. We investigate the effect of the rare earth ion Y on the structure absorption and Raman spectroscopy of ZnWO4 ceramics. In the XRD patterns of Ce doped ZnWO4 some foreign peaks were found and an anormalous change in cell parameter appeared around x . This indicates that the Ce ion has an effect on the structure of ZnWO4 and suggests a solubility limit of Ce in ZnWO4 ceramics. In addition we also calculated the Raman active modes by using group theory and we received 18 modes in Raman active and 16 modes in IR active. The absorption measurement indicates the band gap of ZnWO4 decreases with increasing Y content. The reasons for the above changes are discussed in this presentation. Keywords Effect Y structure absorption Raman spectroscopy ZnWO4 ceramics. 1. Introduction Tungstate crystals are perspective scintillating materials for x-ray detectors γ-ray medical tomographs. In particular the ZnWO4 crystal is a well-known scintillator emitting light at 480 nm under UV X-ray and γ-ray excitation. An important parameter of scintillating material is light emission efficiency and that depends on the transparency of the host crystal in the visible spectral region. Parasite absorption is usually caused by various defects of the lattice. Therefore investigating the nature of defects responsible for absorption in the ZnWO4 is needed in order to solve material science problems. Doping of rare-earth ions into ZnWO4 lattice are expected to influence its chemical and physical properties. However few studies have been reported on doped-ZnWO4 compared to that of other inorganic compounds 1 2 . Furthermore the doping causes a disorder in structure. The disorder in doped rare earth ZnWO4 ceramics is expected to vary .