摘要
众所周知,Cu对ZnS粉末ACEL是不可或缺和不可替代的。因此维持Cu和它的存在形式在ZnS晶粒中的稳定对ACEL的老化致关重要。Cu+在ZnS中具有很高的热扩散率,500℃时热扩散系数已达10-9cm2/s,是各种杂质中热扩散最强的杂质。900℃时几分钟内即可使7~10μm的ZnS晶粒完全激活。CuxS具有很强的离子导电特性,在电场作用下表现出很强的Cu+迁移特性。由于CuxS具有很高的电导率,可视为导体,因此在外电场中ZnS晶粒内的CuxS导电线处于等电位状态。与CuxS导电线电位不同的所有等位面不能与CuxS相交叉而发生扭曲。由于电流的流动方向必须与等位面垂直,所以导致流过ZnS晶粒的大部分电流被汇集到CuxS导线上,并且在导电线上的电流密度分布呈两端弱、中间强的状态。因此在电场作用下CuxS导电线及其周边可能达到很高温度。如上所述,Cu+迁移是必然的,以此可以很好地解释Fischer所观察到的发光线对的老化现象。
It is known that Cu is necessary and no-replacable for ZnS powder ACEL. For this reason, the stability of Cu and its pattern in ZnS particle is the most important for maintenance of luminescence. Cu ^＋ possesses a strong thermo-diffusion with diffusivity of about 10^-9 cm^2/s in ZnS. At 900 ℃, ZnS particle of 7 -10 μm can be activated by Cu^＋ diffusion in few minutes completely. CuxS is a fast-ion conductor emerging very strong Cu^＋ migration in electric field. Because of high conductivity of CuxS, CuxS conductive line in ZnS grain is on the equipotential. The different equipotential surfaces from that of CuxS line are distributed making a detour around the Cu, S line, not across the Cux S line and compressed near both ends of Cux S line. The most of current through the ZnS grain passed the CuxS line because the direction of current must be vertical to the equipotential surfaces. So that, the density of current in the CuxS line is not even, being the largest on the center, and weakening from the center to the ends gradually.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第1期49-52,共4页
Chinese Journal of Luminescence
