Wang Shen-Wei, Yi Li-Xin, Ding Jia-Cheng, Gao Jing-Xin, Guo Li-Da, Wang Yong-Sheng
Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2011 Aug;31(8):2067-70.
CeO2/Tb4O7 superlattices were deposited on P type Si wafers by e-beam evaporation technology. Four typical photoluminescence peaks of Tb3+ ions which located around 488, 544, 588 and 623 nm were obtained after the superlattices annealing in weak reducing atmosphere at high temperature. It was indicated that CeO2 films transferred to amorphous state as the valence transition of Ce4+ --> Ce3+ which was induced by thermal annealing, the energy transfer occurred between Ce3+ ions and Tb3+ ions, and the Tb3+ ions emition could be detected after obtaining the energy from Ce3+ ions. A study about the effect of Tb4O7 thickness on the superlattices photoluminescence showed that the maximum PL intensity as thickness of Tb4 O7 films were about 0.5 nm, the concentration quenching might occur because of the energy transfer among the Tb3+ ions. The annealing conditions research demonstrated that the maximum PL intensity could be obtained as the superlattices annealed at 1 200 degrees C for 2 hour. Further investigation inferred that the concentration of Ce3+ ions, Oxygen vacancy defects and the distance between Ce3+ ions and Tb3+ ions play an important role in the annealing process.
采用电子束蒸发技术在P型硅片上沉积了CeO₂/Tb₄O₇超晶格。超晶格在高温弱还原气氛中退火后，获得了位于488、544、588和623nm附近的Tb³⁺离子的四个典型光致发光峰。结果表明，热退火诱导Ce⁴⁺→Ce³⁺价态转变，CeO₂薄膜转变为非晶态，Ce³⁺离子与Tb³⁺离子之间发生了能量转移，Tb³⁺离子从Ce³⁺离子获得能量后可检测到其发射。关于Tb₄O₇厚度对超晶格光致发光影响的研究表明，当Tb₄O₇薄膜厚度约为0.5nm时，PL强度最大，由于Tb³⁺离子之间的能量转移可能会发生浓度猝灭。退火条件研究表明，超晶格在1200℃退火2小时可获得最大PL强度。进一步研究推断，Ce³⁺离子浓度、氧空位缺陷以及Ce³⁺离子与Tb³⁺离子之间的距离在退火过程中起重要作用。
