Si基CeO_2薄膜的发光特性  

Photoluminescence Properties of Si-based CeO_2 Films

作　　者：王申伟[1] 衣立新[1] 丁甲成[1] 高靖欣[1] 王永生[1] 

机构地区：[1]北京交通大学光电子技术研究所发光与光信息技术教育部重点实验室,北京100044

出　　处：《发光学报》2010年第5期762-766,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金(60977017)资助项目

摘　　要：利用电子束蒸发技术在p型硅衬底上沉积了200 nm厚的CeO2薄膜样品,将样品置于弱还原气氛中高温退火后,观察到薄膜在385,418 nm以及445 nm左右出现三个明显的发光峰。结合激发光谱、吸收光谱以及XRD分析表明：CeO2薄膜在高温下容易发生失氧反应,出现Ce4＋→Ce3＋离子转变,Ce3＋离子在紫外光的激发下,电子由O2p跃迁到5d能级,再由5d能级向4f能级跃迁,从而产生强烈的蓝紫外发射,而445 nm左右的发光峰则来自于SiO2薄膜的缺陷发光。样品选择9001 200℃不同温度退火,并且在1 200℃下进行了不同时间的退火。研究结果显示：在1 200℃下进行2 h的退火,薄膜发光强度达到最大。CeO2 films were deposited on p type Si wafers by e-beam evaporation technology.Three photoluminescence peaks which located around 385,418 nm and 445 nm were obtained after annealing in weak redu-cing atmosphere at high temperature.It was indicated that CeO2 films transferred to amorphous state as the valence conversion of Ce4＋→Ce3＋,which was induced by reducing atmosphere annealing.The PL spectrum of 385 nm and 418 nm was assigned to the transition from 5d energy level of Ce3＋ ions to 2F7/2 and 2F5/2 manifolds of 4f energy level,respectively,while the peak around 445 nm was assigned to the O vacancies of SiO2.Furthermore,the changes of PL intensity in CeO2 films annealed with different temperature and time were also investigated.The maximum PL intensity was obtained after the films annealing at 1 200 ℃ for 2 h compared with other temperature and time.It was indicated that valence conversion of Ce4＋→Ce3＋ was enhanced by increasing annealing temperature and time,that is,the PL intensity of the films was also enhanced because of the increasing of Ce3＋ ions,however,the energy transfer between Ce3＋ and Ce3＋ ions,occurred as excessive Ce3＋ ions were formed in the films,resulting in concentration quenching.

关 键 词：CEO2 光致发光 能量传递 

分 类 号：O472.3[理学—半导体物理]