(Ce，Yb）共掺杂氧化硅薄膜的发光特性及结构

采用磁控溅射技术在单晶硅衬底上制备了稀土（Ce，Yb）共掺杂氧化硅薄膜，研究了薄膜样品的结构和下转换发光性质。样品的发光光谱显示，在He-Cd激光器325 nm线的激发下，Ce3+离子的发光强度较弱而Yb3+离子的发光较强；Yb3+的发光随着退火温度的升高逐渐增强；这些结果加上样品的激发光谱和衰变光谱，都显示样品中发生了Ce3+ 到Yb3+的能量传递过程。X射线衍射结果表明，样品在高温退火时（大于1 000 ℃）出现晶化，形成了Ce和Yb的硅酸盐结构。笔者认为利用高温退火形成Ce的硅酸盐结构可以明显增强Yb3+的发光，从而提高薄膜的下转换发光效率。

Photoluminescence and structure of (Ce,Yb) co-doped silicon oxides

Cerium (Ce) and ytterbium (Yb) co-doped silicon oxide (SiOx: Ce, Yb) thin films were deposited by using magnetron co-sputtering technique. The down-conversion photoluminescence (PL) properties and structural evolution of the films after thermal treatments were studied. Under the excitation of a He-Cd 325 line, light emissions from the Ce3+ ions are rather weak while quite strong from the Yb3+ ions; the Yb PL intensity increases with elevating the anneal temperature, and both PL excitation and decay spectra indicate that energy transfer from Ce3+ to Yb3+ ions has taken place in the oxides. X-ray diffraction patterns show that Ce and Yb-related silicates have formed as the annealing temperature is higher than 1 000 ℃. The authors believe that the Yb PL can be enhanced greatly by forming high-luminescent Ce3+-related silicates in the oxide films, and thus increase the down-conversion efficiency.