A STUDY ON EXCITATION AND DE-EXCITATION MECHANISMS OF HIGHLYRARE-EARTH MATERIAL-DOPED SILICON THIN FILMS

本研究的目标是利用高度掺杂的硅（Si ： Er）薄薄膜的激发和去激发机制。Er doping into Si thin films has been carried out by the laser ablation technique that is able to control easily the Er density over 10-D119-D121-D1cm-D1.对cw和脉冲刺激的光致发光发生在20 K至房间温度范围内。Intense 1.54-m-emission originating from intra-4 f shell transitions in Ery D13+ Eye D1ions has been observed even at room temperature。The increase of Er density over two orders of magnitude cannot immediately result in a linear increase in Er D13+ y D1-em？int\。The time res\measurement indicated that the change in the rise time of Ery D13+ Em\directly shows that Ery D13 + Em\D1ions are excited indirectly by the energy transfer associated with the recombination of electron-hole pairs generated optically in Si host。根据对能量转移基础的时间响应测量的分析，发现了Ery D13 + Ery D1 ions对Ery D13+ Ery D13 + Ery D1的抑制作用产生了响应性D13+ Ery D1-在高掺杂硅薄膜中的发射强度。硅的局部结构：通过对扩展X射线吸收精细结构测量和基于多散射理论的X射线吸收结构模拟的组合分析进行了调查。这个结果包括光学活性氢中心的主要本地结构是六折绑定到邻近氧原子，它是一个C-D24 V-D2对称性。

The objective of this research is to understand the excitation and de-excitation mechanisms of highly Er-doped Si (Si : Er) thin films. Er doping into Si thin films has been carried out by the laser ablation technique that is able to control easily the Er density over 10ィイD119ィエD1 to 10ィイD121ィエD1 cmィイD1-3ィエD1. The photo-lumeinescence for cw and pulse excitations has been achieved at the temperature range from 20K to room temperature. Intense 1.54 μm-emission originating from intra-4f shell transitions in ErィイD13+ィエD1 ions has been observed even at room temperature. The increase of Er density over two orders of magnitude can not immediately result in a linear increase in ErィイD13+ィエD1-emission intensity. The time response measurement indicated that the change in the rise time of ErィイD13+ィエD1-emission directly shows that ErィイD13+ィエD1 ions are excited indirectly by the energy transfer associated with the recombination of electron-hole pairs generated optically in Si host. From the analysis of time response measurement on the basis of the energy transfer, it was found that the decrease of the excitation efficiency of ErィイD13+ィエD1 ions was responsible for the suppression of ErィイD13+ィエD1-emission intensity in highly Er-doped Si films. The local structure of the Si : Er films has been investigated by the combined analysis of the extended x-ray absorption fine structure measurement and the x-ray absorption structure simulation based on the multiple-scattering theory. This result concludes that dominant local structure of optically active Er centers is sixfold bonding to neighboring oxygen atoms, that is, a CィイD24VィエD2 symmetry.