【作者】 张昌盛；

【导师】 张峰；

【作者基本信息】 中国科学院研究生院（上海微系统与信息技术研究所） ， 微电子学与固体电子学， 2005， 博士

【摘要】 Er³⁺在石英基体材料中受激光致发光的波长大约是1540nm,这个波长是石英光纤的最小损耗窗口,因而是以石英光纤为基础的光通讯的标准波长之一。掺铒光纤放大器（EDFA）作为获得光增益的媒质是光纤通讯系统中极其重要的组成部分。当前正在快速发展的城域网（MAN）、局域网（LAN）以及光纤到户（FTTH）等系统中对波分复用（WDM）/密集波分复用（DWDM）光信号能量衰减的补偿需要可集成的紧凑型、低成本掺铒光波导放大器（EDWA）。然而,Er³⁺在体硅中具有固溶度低和发光强度温度淬灭强的缺点,难以达到设计光波导放大器的要求。一种新颖的敏化发光技术使获得室温高效硅基掺铒发光成为可能。在掺铒的SiO₂中形成Si-nc,利用Si-nc对Er³⁺的敏化作用可以提高Er³⁺对泵浦光的有效吸收截面;利用Si-nc带隙和Er³⁺跃迁能量之间较大的不匹配可以抑制温度淬灭效应。 本文利用离子注入方法制备了富硅氧化硅（SRSO）和掺铒富硅氧化硅（ErSRSO）材料,研究了材料微观结构和Er的化学状态随退火温度的演变。实验结果表明注入SiO₂的富余Si原子经历了偏析集聚形成a-Si纳米颗粒继而在更高温度转变成nc-Si的演化过程;在900℃以上温度退火,形成非晶SiO_x层包覆nc-Si的壳层结构;约900℃退火,形成具有光学活性的Er-O发光中心。 研究了富硅氧化硅和掺铒富硅氧化硅的光致发光特性以及退火对他们的影响。结果表明Er³⁺的出现和浓度升高都对Si-nc的光致发光有淬熄作用,证实了Si-nc与Er³⁺强耦合模型的正确性;发现壳层结构中残余非晶硅层是激发态Er离子非辐射去激发的通道之一,由此引起的能量背迁移是Er离子光致发光在T>150K温度淬灭的主要因素。 考虑到Er³⁺通过Si-nc间接被激发的过程,我们对描述激发态Er³⁺的速率方程进行了改写。与SiO₂中Er³⁺直接被激发不同,从ErSRSO系统速率方程的解中得到1/T_rise与φ是非线性关系,并被实验结果所证实。根据实验结果拟合得到我们所更多还原

【Abstract】 The stimulated photoluminescence （PL） of Er ions in a silica host matrix at the standard 1540nm optical communication wavelength corresponds to the minimum attenuation in silica based fibers. EDFAs （Erbium-Doped Fiber Amplifiers） are important components for optical communication system as optical gain media. Compact and cost-effective integrated EDWAs （Erbium-Doped Waveguide Amplifiers） are required to compensate the attenuation of WDM/DWDM （（Dense） Wavelength Division Multiplexing） in MANs （Metropolitan Area Network）, LANs （Local Area Network） and FFTH （Fiber to the Home）. However, the main drawbacks of Er-doped Silicon for designing integrated EDWA are the low Er solubility and the very strong PL intensity thermal quenching. A novel sensitization technique for Er PL makes the efficient emission from Er-doped silicon-based materials reality. In SiO₂ host, the optical pumped Si-ncs are used as sensitizers for Er³+ enhanced the Er³+ effective cross section greatly. The Er PL thermal quenching is restricted due to the large mismatch between the Si-nc bandgap energy and the Er transition energy.The Si-rich silicon oxidation （SRSO） and the Er-doped Si-rich silicon oxidation （ErSRSO） materials were prepared by ion implantation. The evolutions of microstructure and Erbium chemical state with the increasing of annealing temperature were investigated. The excessive Si in SiO₂ host separates out to form amorphous Si nanocluster by thermal treatment. With the increasing of annealing temperature, the a-Si clusters transform to silicon nanocrystals. A shell configuration with Si-nc core enwrapped by amorphous SiO_x obtained at T>900℃. The optical active emission centre related to Er-0 obtained by 900℃ annealing.The PL properties of SRSO and ErSRSO and the influence of the annealing were investigated. The results show that the presence of Er³+ induced the quenching ofSi-nc PL intensity. It confirms that the model of strong coupling between Si-nc and Er ions is correct. The residual a-Si in shell area after annealing is one of the non-radiative de-excitation channels for the excited Er3+. The Er PL thermal quenching at T>150K is mainly induced by the energy back transfer through this channel.Considering the increase of excited state Er3+ through the energy transfer from nc-Si, we developed the new rate equations governing the populations of excitons in Si-nc and the Er3+ metastable state. A nonlinear relation between l/rm￡.and<t> wasobtained. The effective cross section was determined for indirect excitation of ErJ* by fitting the curve of l/rn,c vs.<I>. For our ErSRSO samples, the effective cross sectionis up to four orders of magnitude higher than the Er3+ direct optical absorption.A theoretical model was developed based on Forster theory by analogy with the rare-earth codoped systems. The coupling and energy transfer between Si-nc and ErJ’ can be explained by non-radiative dipole-dipole resonance interaction mechanism. By analysis the photoluminescence decays from Si-ncs with and without Er3". we evaluate Forster critical radius Ro of the interaction between optically active Er3* andSi-ncs. The Ro value of our ErSRSO samples is 1.64nm. The energy transfer quantumefficiency evaluated in terms of Rlt and the average separation distance between Si-nc and Er3+is 17.45%.更多还原