Fabrication of ErSiO self-organized superlattice thin films and evaluation of the 1.54μm optical waveguide amplification characteristics

研究了具有自组织超晶格结构的ErSiO新材料及其用于1.54μm光波导放大的可能性。2003财政年度，利用分子束外延、纳米结构多孔硅和溶胶凝胶法制备了ErSiO新薄膜。每种方法都可以成功地制备出ErSiO晶体材料。它们都表现出了ErSiO超晶格的晶体结构特征，以及由于Er4f-4f跃迁中Stark分裂而在室温下尖锐而精细的1.54μm发光光谱。2004财年，我们研究了厚度超过100 nm的ErSiO薄膜的新制备方法的开发和工艺改进。利用这些改进的ErSiO薄膜，研究了ErSiO超晶格的自组织机制、详细的晶体结构、电学性质，以及产生特殊发光光谱和短荧光寿命的原因。第一，控制…Er，Si，O的比例为1：2：2.4时，特别是对O的控制，对于具有独特发光光谱和较快荧光寿命的Er-SiO晶体超晶格的生长至关重要。我们还尝试了激光烧蚀的方法，以期在较低的工艺温度下获得改进的ErSiO超晶格，并对溶胶-凝胶法和MOMBE法的工艺进行了改进。在90 0~10 0 0℃的温度范围内，获得了较低约2 0 0℃的ErSiO晶态薄膜。在2005财政年度，详细研究了极快荧光寿命的起源，S的荧光寿命为10-20μ，而掺Er的硅相关材料的荧光寿命只有几ms。通过改变ErSiO薄膜的光密度，发现快速荧光寿命就是ErSiO本身的辐射寿命，这可能是由于ErSiO薄膜中Er~(2+)和Lt；3+&Gt~(2+)离子的结晶场非常均匀和强烈所致。研究了ErSiO光波导的传输特性和上转换特性。结果表明，ErSiO的浓度大于10μ/cm3，辐射寿命为10-20μS，是一种很有前途的1.54μm受激发射和光放大材料。

This study deals with the ErSiO new materials with a self-organized superlattice structure and its possibility for the 1.54μm optical waveguide amplification.In the fiscal year 2003, fabrication of ErSiO new thin films were developed using MOMBE, nano-structured porous silicon and sol-gel methods. ErSiO crystalline materials could be successfully formed by every method. They all show crystalline structures characteristics of ErSiO superlattice and also sharp and fine-structured 1.54μm luminescence spectra at room temperature due to Stark splittings in the Er 4f-4f transitions.In the fiscal year 2004, developments of a new fabrication method and the process improvements for ErSiO films thicker than 100 nm were studied. Using these improved ErSiO thin films, the self-organization mechanisms of ErSiO superlattice, detailed crystalline structures, electrical properties, and the origins of the peculiar luminescence spectra and the short fluorescence lifetime were investigated. First, contro … More l of the ratio of Er, Si and O at 1:2:2.4, especially control of O, was found to be most important for the growth of ErSiO crystalline superlattices with their peculiar luminescence spectra and fast fluorescence lifetime. A laser ablation method was also attempted to obtained improved ErSiO superlattice at lower process temperature together with process improvements of sol-gel and MOMBE methods. ErSiO crystalline thin films were obtained at 900-1000℃, about 200℃ lower than before. Possibility of epitaxial growth on tilted Si(100) by MOMBE was shown.In the fiscal year 2005, origins of very fast fluorescence lifetimes, 10-20μs compared to several ms in Er-doped Si-related materials, were studied in detail. By varying the optical density in ErSiO thin films, it was found that the fast fluorescence lifetime was the radiative lifetime itself of ErSiO, which may be due to very uniform and strong crystalline fields on Er^<3+> ions. ErSiO optical waveguides were formed and the transmission properties and up-conversion characteristics were studied.In conclusion, ErSiO with the Er concentration higher than 10^<20>/cm^3 and the radiative lifetime of 10-20μs is a very promising materials for the stimulated emission and light amplification at 1.54μm. Less