Study On Er-Doped Silicon-Rich Silicon Oxidation Prepared By Ion Implation

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/rmï¿¡.and wasobtained. The effective cross section was determined for indirect excitation of ErJ* by fitting the curve of l/rn,c vs.. 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%.