稀土掺杂多孔硅的蓝光发射

The blue photoluminescence from rare earths-doped porous silicon

用电化学方法对多孔硅薄膜进行了稀土 (Pr,Dy ,Sc)离子的化学掺杂 .用扫描电镜研究了多孔硅薄膜的表面形貌 ,用卢瑟福背散射谱研究了稀土离子在多孔硅薄膜中的分布情况 .利用荧光分光光度计分析了样品的光致发光特性 ,发现稀土掺杂增强了多孔硅的蓝光发射 ,尤其是Dy的掺杂可产生较强的蓝光发射 ,其强度可与多孔硅的红光强度相比较 ,适当的Pr和Sc的掺杂也可一定程度地增强多孔硅的蓝光发射 .稀土掺杂多孔硅后产生蓝光发射的可能机理为 :稀土掺杂引入新的表面态 ,形成硅、氧、稀土间新的键合方式O—Si—O—Re—O ,从而在多孔硅表面形成新的发光中心 ;稀土离子丰富的能态在多孔硅发光过程中起到了能量传递作用 ,从而增强了多孔硅的蓝光发射 .

Rare earth (Pr, Dy, Sc) ions were embedded into porous silicon films by electrochemical method. Scanning electron microscope was employed to characterize the surface morphology of samples. The distribution of rare earth ions embedded in the porous silicon films was observed by Rutherford backscattering spectrometry. Fluorescence photo-spectrometer was used to analyze the photoluminescence properties of the samples. The blue emission of porous silicon was increased after rare earths' doping. Moreover, when Dy was doped, intense blue light was obtained. The intensity is approximately equal to the red light intensity of the porous silicon without doping. The blue light can be increased in a certain extent when proper amounts of Pr and Sc were embedded into. The mechanisms of blue emission may be: new surface states were introduced upon rare earths' doping and the new bonding O—Si—O—Re—O was formed, so the new light emission centers appear on the surface of porous silicon. The rich energy states of rare ions may play a role in energy transfer so as to increase the blue emission.