Department of Materials Science and Engineering, University of Tabriz, Tabriz, Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Dec;83(1):592-7. doi: 10.1016/j.saa.2011.09.009. Epub 2011 Sep 16.
In the present work, the effect of CeO(2) as the passive agent on glassy structure of Li(2)O-Al(2)O(3)-SiO(2)-TiO(2) (LAST) material for production of a new amorphous semiconductor has been investigated. Optical properties and vibrational spectroscopy of the samples have been studied using UV-Vis and FTIR absorption spectra, respectively. Accordingly, structural variations of 0-1.5% CeO(2):LAST glasses were evaluated by calculation of density, molar volume, Urbach band tailing, direct and indirect optical band gaps, Fermi energy level and metallization criterion. Eventually for the analysis of the variation of energy level in presence of passive agent CeO(2), Licciardello's model for glassy semiconductors was utilized. Results of the investigation illustrates that while Ce(3+) ions could be regarded as the color agents due to spin allowed f-f transition, Ce(4+) ions might have a destructive influence on negative-U centers (color centers) of the glass and hence, reduce the recombination centers in the band gap of the glass.
在本工作中，研究了 CeO(2) 作为被动剂对 Li(2)O-Al(2)O(3)-SiO(2)-TiO(2) (LAST) 材料的玻璃结构的影响，该材料用于生产一种新型非晶半导体。使用 UV-Vis 和 FTIR 吸收光谱分别研究了样品的光学性质和振动光谱。因此，通过计算密度、摩尔体积、Urbach 带尾、直接和间接光学带隙、费米能级和金属化标准，评估了 0-1.5% CeO(2):LAST 玻璃的结构变化。最后，为了分析在存在被动剂 CeO(2)的情况下能级的变化，利用了玻璃半导体的 Licciardello 模型。研究结果表明，虽然 Ce(3+)离子由于自旋允许的 f-f 跃迁可以被视为颜色剂，但 Ce(4+)离子可能对玻璃中的负-U 中心（色心）产生破坏性影响，从而减少玻璃带隙中的复合中心。
