Rare earth-doped polycrystalline zinc oxide electroluminescent ceramics
Rare earth-doped polycrystalline zinc oxide electroluminescent ceramics
复制标题
稀土掺杂多晶氧化锌电致发光陶瓷
DOI：
10.1016/s0022-3697(96)00067-4
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发表时间：
1996
影响因子：
4
通讯作者：
J. Ronfard
中科院分区：
文献类型：
--
作者：
S. Bachir;C. Sandouly;J. Kossanyi;J. Ronfard
制备了三价稀土离子（Eu3+、Tm3+、Er3+）掺杂氧化锌陶瓷。人们发现它们在受到电场作用时会发光，并且发光光谱是三价稀土离子的光谱。与具有相同结构（夹在两种金属焊料之间的多晶半导体氧化锌颗粒）和密切相关的化学成分的压敏电阻相比，这些陶瓷表现出较弱的非欧姆行为，可以将其视为具有金属-半导体-金属（M-S-M）结构的电致发光系统。解释所观察到的发光的机制基于插入半导体晶格的三价稀土离子的热电子碰撞激发。根据压敏电阻模型，电子是由存在双肖特基势垒的晶界处的热电子发射产生的。发光强度随施加电压的变化可以估计氧化锌颗粒的尺寸，并将其与扫描电子显微照片测量的尺寸进行比较。
Trivalent rare earth ions (Eu3+, Tm3+, Er3+)-doped zinc oxide ceramics have been prepared. They were found to be luminescent when submitted to electric fields and the luminescence spectra are those of the trivalent rare earth ions. Compared to Varistors which have the same structure (a polycrystalline semiconducting zinc oxide pellet sandwiched between two metallic solders) and a closely related chemical composition, these ceramics present a weak non-ohmic behaviour and they can be considered as electroluminescent systems with a metal-semiconductor-metal (M-S-M) structure. The mechanism which explains the observed luminescence is based on a hot electron impact-excitation of the trivalent rare earth ions inserted into the semiconducting lattice. According to the model of Varistors, the electrons are generated by thermionic emission at the grain boundaries where double Schottky barriers are present. The variation of the luminescence intensity with the applied voltage allows an estimation of the size of the zinc oxide grains which has been compared to that measured from the scanning electron micrographs.