Thermoluminescence study of stoichiometric LiNbO3 crystals
Thermoluminescence study of stoichiometric LiNbO3 crystals
复制标题
化学计量LiNbO3晶体的热释光研究
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
J. Cahill
中科院分区：
文献类型：
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作者：
M. Chirila;N. Garces;L. Halliburton;D. Evans;S. Basun;R. Meltzer;W. Yen;S. Rutkowski;D. Shumov;J. Cahill
利用热释光（TL）、光吸收和电子顺磁共振（EPR）表征了掺杂mg的化学计量LiNbO3的点缺陷。当这些晶体在77 K下辐照然后快速加热时，在94 K附近观察到宽TL发射，峰值在440 nm。X射线和带隙以下激光（325和355nm）在产生TL峰方面同样有效。在激发过程中，空穴被困在锂空位附近的氧离子上，电子被困在规则晶格位置的铌离子上。这两种缺陷都具有特征的EPR光谱，捕获的电子中心在1200nm处有一个光学吸收峰。当温度升高时，电子在94k附近变得热不稳定，并迁移到发生辐射复合的困空穴位。我们认为，名义上存在的Fe3+杂质的近边电荷转移吸收带提供了带隙下光最初产生单独捕获的ho的机制。
Thermoluminescence (TL), optical absorption, and electron paramagnetic resonance (EPR) have been used to characterize point defects in Mg-doped stoichiometric LiNbO3. A broad TL emission, peaking at 440 nm, is observed near 94 K when these crystals are irradiated at 77 K and then rapidly warmed. X rays and below-band-gap lasers (325 and 355 nm) are equally effective in producing the TL peak. During excitation, holes are trapped on oxygen ions adjacent to lithium vacancies and electrons are trapped on niobium ions at regular lattice sites. These defects both have characteristic EPR spectra, and the trapped electron center has an optical absorption band peaking at 1200 nm. Upon warming, the electrons become thermally unstable near 94 K and migrate to the trapped-hole sites where radiative recombination occurs. We suggest that the near-edge charge-transfer absorption band from Fe3+ impurities, nominally present, provides the mechanism by which below-band-gap light initially produces the separately trapped ho...