Tunneling-recombination luminescence between Ag0 and Ag2+ in KCl:AgCl
Tunneling-recombination luminescence between Ag0 and Ag2+ in KCl:AgCl
复制标题
KCl:AgCl 中 Ag0 和 Ag2 之间的隧道复合发光
DOI：
10.1103/physrevb.17.4765
复制
发表时间：
1978
影响因子：
3.7
通讯作者：
P. Yuster
中科院分区：
文献类型：
--
作者：
C. J. Delbecq;D. L. Dexter;P. Yuster
KCl：AgCl晶体的适当处理导致电子作为银原子Ag/sup 0/和空穴作为AgCl/sub 4//sup 2 -/，Ag/sup 2 +/被捕获。在T < 90 K时，这种晶体中Ag/sup 0/的光激发产生激发后持续数小时的发光。提出的证据表明，这余辉的结果从附近的Ag/sup 0/和Ag/sup 2 +/对之间的电子-空穴隧穿复合，类似于我们以前报道的Ag/sup 0/-Cl/sub 2/-隧穿复合的研究。我们已经表明，Ag/sup 2 +/中心参与的发射过程中优先取向的各向异性Ag/sup 2 +/在6 K激发偏振光和观察到的余辉是偏振的。当升温到50 K时，其中优先取向的Ag/sup 2 +/可以改变取向，发生极化程度的强烈反转，其最终衰减到零。如果我们假设：（i）隧穿-复合机制，其中发射辐射的电矢量的取向取决于Ag/sup 0/相对于Ag/sup 2 +/的位置，以及（ii）隧穿是各向异性的，并且取决于Ag/sup 0/相对于各向异性的Ag/sup 2 +/的位置，则可以理解这种发光的特性。后一种假设是基于Ag/sup 2 +/络合物的四对称性（d-样）。在衰减动力学、极化度和极化反转方面，理论和实验之间取得了很好的定量一致。«少
Appropriate treatment of a KCl:AgCl crystal results in the trapping of electrons as silver atoms, Ag/sup 0/, and positive holes as AgCl/sub 4//sup 2 -/, Ag/sup 2 +/, centers. Optical excitation of Ag/sup 0/ in such a crystal at T < 90 K produces a luminescence which lasts for many hours after the excitation. Evidence is presented which indicates that this afterglow results from electron-hole tunneling recombination between nearby Ag/sup 0/ and Ag/sup 2 +/ pairs, similar to the Ag/sup 0/-Cl/sub 2/- tunneling-recombination studies we previously reported. We have shown that Ag/sup 2 +/ centers are involved in the emission process by preferentially orienting the anisotropic Ag/sup 2 +/ at 6 K by excitation with polarized light and observing that the afterglow is polarized. Upon warming to 50 K, where the preferentially oriented Ag/sup 2 +/ can change orientation, a strong reversal in the degree of polarization occurs which finally decays to zero. The characteristics of this luminescence can be understood if we assume: (i) a tunneling-recombination mechanism in which the orientation of the electric vector of the emitted radiation depends on the position of the Ag/sup 0/ relative to the Ag/sup 2 +/ and (ii) the tunneling is anisotropicmore » and depends on the location of the Ag/sup 0/ relative to the anisotropic Ag/sup 2 +/. The latter assumption is based on the tetragonal (d-like) symmetry of the Ag/sup 2 +/ complex. Good quantitative agreement between theory and experiment has been obtained on the decay kinetics, the degree of polarization, and the polarization reversal.« less