退火对Cr^(3+)离子掺杂Al_2O_3薄膜的结构及发光性能影响  

Influence of annealing on structural and photoluminescence properties of Cr^(3+) doped Al_2O_3 thin films

作　　者：孙乃坤[1] 杜宝盛 高印博[1] 柳峰[1] 蔡宗岐[1] 赵美星[1] 

机构地区：[1]沈阳理工大学理学院,辽宁沈阳110159

出　　处：《功能材料》2013年第13期1859-1862,共4页Journal of Functional Materials

基　　金：沈阳理工大学博士启动专项基金资助项目(沈理工科[2008]20号)

摘　　要：用脉冲激光沉积技术在Si(100)基底上制备了纯Al2O3、掺杂浓度为0.3%、1%(质量分数)的Cr3+∶Al2O3薄膜。制备态的薄膜为立方γ-Al2O3结构,经800℃真空条件下退火1h样品的结晶度有所提高,呈现α-Al2O3相与γ-Al2O3相的衍射峰。薄膜基本保持了靶材中原有各元素成分比例,平均粒径为250nm,形貌为条形。与Al2O3粉体相比,制备态薄膜在386nm处的发光峰强度明显提高。这可归因于薄膜中氧空位的增加使双氧空位吸收电子所产生的F2+色心浓度提高。薄膜经真空退火后在332、398nm附近的发光峰强度明显增强,这是由于薄膜中氧空位的增加提高了F+、F色心浓度。与此同时,制备态薄膜在386nm附近发光峰经退火后由386nm蓝移至381nm,可归因于退火后制备态薄膜的内应力得到了释放。1%(质量分数)Cr3+掺杂薄膜在646、694nm出现Cr3+离子由4 T2能级跃迁至4 A2能级及由E-能级跃迁至4 A2能级产生的荧光发光峰。Al2O3 and Cr3＋-doped Al2O3（0.3%,1wt%） thin films have been grown on Si（100） substrates by pulsed laser deposition.The as-prepared films show cubic γ-Al2O3 structure.After vacuum annealing at 800℃ for 1h,the crystallinity of the sample was improved.The annealed film presents the diffraction peaks of α-Al2O3 and γ-Al2O3.The SEM image reveals that crystal grains of the films have an average grain size of 250nm and a morphology of bar.The electron energy spectrum shows that element compositions of thin films are almost the same as the according targets.Compared with Al2O3 powder,the intensity of the luminescence peak at 386nm of Al2O3 thin films greatly enhances.This can be ascribed to an increase of oxygen vacancies in the thin films and the concentration of F2＋ color centers caused by double-oxygen-vacancy absorbing electrons accordingly enhances.Compared with Al2O3 thin film,the intensity of the luminescence peak at 332 and 398nm of the annealed Al2O3 thin films greatly enhances,which can be ascribed to an increase of the concentration of color centers（F＋,F）.The blue shift from 386 to 381nm of emission peak of Al2O3 thin film after annealing was mainly attributed to release of the internal stress.The photoluminescence spectra of 1wt% Cr3＋-doped Al2O3 thin film show two emission peaks at 694 and 646nm,which are caused by electron transition of Cr3＋ ions from E-to 4A2 and 4T2 to 4A2.

关 键 词：脉冲激光沉积 Cr3+掺杂的氧化铝薄膜 荧光光谱 真空退火 

分 类 号：TN383[电子电信—物理电子学]