電子線励起紫外発光ZnAl_2O_4蛍光体の焼成条件依存性

摘要

ZnAl_2O_4 phosphor which shows ultra violet emission under the electron beam excitation has been investigated for the ultra violet emitting devices. In this work, we investigated the dependence of structure and the luminescence of ZnAl_2O_4 phosphor on firing condition which prepared by solid-phase reaction. The structure and the luminescence properties of the ZnAl_2O_4 were drastically changed by the firing conditions (firing temperature, atmosphere, and ZnO/α-Al_2O_3 molar ratio, etc.). From the results of XRD, PLE and CL measurements, it is thought that ZnAl_2O_4 has a bandgap of about 7 eV and the UV emission is caused by oxygen vacancy and the energy level caused by Zn excess in the crystal.%電子線励起によって紫外発光を示すZnA1204は新規紫外発光デバイス用蛍光体として期待されている．本稿では固相合成法により作製したZnAl_2O_4の構造及び発光の焼成条件依存性について調べた．作製されたZnAl_2O_4の構造や発光は，焼成時の温度，雰囲気，ZnOモル比といった焼成条件に顕著に依存する傾向が示され，XRD，PLE，CL等の結果からZnAl_2O_4のバンドギャップが約7eVであり，紫外発光は酸素欠陥と過剰添加Znによる準位であると推察した．