Observation of charge transfer process for optical emission of rare-earth dopant using electric probing technique
Observation of charge transfer process for optical emission of rare-earth dopant using electric probing technique
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利用电探测技术观察稀土掺杂剂光发射的电荷转移过程
DOI：
10.1016/j.jlumin.2011.12.041
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发表时间：
2012
影响因子：
3.6
通讯作者：
and B. Hamilton
中科院分区：
文献类型：
--
作者：
M. Ishii;S. Harako;X. Zhao;S. Komuro;and B. Hamilton
采用电测量技术，即阶跃函数紫外光辐照复阻抗相位响应，研究了钐掺杂二氧化钛（TiO2：Sm）的激发和去激发过程中的电荷传播动力学。阻抗测量的探测频率被广泛地改变，并且发现了强调特定电荷传播路径的临界频率。在1kHz的临界频率以上，从光激发态到基态的跃迁通过快速的，通过比较在连续紫外光下获得的频率响应，（光激发态）和在黑暗中（基态），快速的路径被分配到电荷复合的缺陷掺杂剂复合物中的TiO 2：Sm，这是一致的，在传统的光学测量中观察到的发光的持久性。与光跃迁无关的慢路径可以用激发电荷的耗散来解释。在低于临界频率<1kHz时，证实了与电荷耗散解释一致的类似路径。
Charge propagation dynamics for the excitation and de-excitation of samarium doped titanium dioxide (TiO2:Sm) were observed by an electric measurement technique, namely, the phase response of complex impedance to step-function UV irradiation. The probing frequency for the impedance measurement was widely changed, and a critical frequency that emphasizes a specific charge propagation path was found. Above the critical frequency of 1kHz the transitions from the photo-excited state to ground state progressed via a rapid, and a slow charge propagation path. Through a comparison of the frequency responses obtained under continuous UV light (photo-excited state) and in the dark (ground state), the rapid path was assigned to charge recombination in a defect-dopant complex in TiO2:Sm, which is consistent with the persistence of luminescence observed in conventional optical measurements. The slow path that is not associated with the optical transition was explained by a dissipation of excited charges. Similar path consistent with the charge dissipation explanation was confirmed below the critical frequency <1kHz.