Doped Er Luminescence Characteristics Of Thin Film Materials

We human being live in the 21th century, the development and advances in science and technology make people require more and more information. The communication and interconnect with photon as the carrier of information will be the next generation of communication scheme. The 1.54um emission from the intra-4f transition of Er ions has attracted much attention on the application of optic-electric integration technology. The studies are mainly focused on how to improve the luminescence efficiency of Er doped materials and devices, and on the energy transfer mechanism and physical and chemical environment for Er luminescence. Under above background, the works in this thesis focus on the optical properties of Er doped HfO₂ thin film, Er-Tm-codoped Al₂O₃ thin film and Er doped Si-rich Al₂O₃ film.The first part is investigating the Er doped HfO₂ thin film grown by the pulse laser deposition (PLD) and ion implantation. At room temperature, we observed the main PL peak at 1533 nm correspond to intra-4f transitions of Er³⁺and two stark splitting peaks located at 1490nm and 1564nm. In order to investigate more information concerning the luminescence mechanism of Er³⁺, PL excitation (PLE) spectrum of an Er³⁺in HfO₂ film were measured at room temperature. Besides several peaks from intra-4f Er³⁺ transitions, the samples also show strong PL even when excited with a wavelength of which Er³⁺ does not absorb energy, which indicates a carrier-mediated process involving Er-related levels. The PL study in ultraviolet wavelength proves the O vacancies serve as sensitizer in Er doped HfO₂ thin film, which can effectively transfer the energy to the Er³⁺. The PLE spectrum shows that besides the oxygen vacancy acting as sensitizers for Er luminescence, there should be another sensitizer. Which is supported by the existence of Hf element in the films examined by the XPS measurement and the luminescence from the Hf is resonant with the energy level of Er. So we propose that the Hf element itself can also serve as sensitizer. The sensitizers make Er³⁺ excitation in a broad energy range.In the second part, Er-Tm-codoped Al₂O₃ thin film with different [Tm] to [Er] ratios have been synthesized by cosputtering from separated Er, Tm, Si, and Al₂O₃ targets. The temperature dependence of PL from Er-Tm-codoped Al₂O₃ thin film was studied. Three bands, peaked at 1470, 1533 and 1800 nm respectively, were observed, which were assigned to the emissions corresponding to the transitions Tm³⁺: ³H₄â†'³F₄, Er³⁺: ⁴I_13/2â†'⁴ I_15/2 and Tm³⁺: ³F₄â†'³H₆, respectively. A fairly flat emission band covering the wavelength range of 1.4-1.7 um can be obtained by optimizing the concentrations of Er³⁺ and Tm³⁺ ions. The 1533 nm peak intensity of Er-Tm-codoped Al₂O₃ film increases by a factor of five with temperature increasing from 14 to 298 K. This phenomenon is attributed to complicated ET processes between Er³⁺ and Tm³⁺at different operating temperatures.In the third part, the Er: SRA multilayer film has been synthesized by magnetron sputtering. The intensity of Er³⁺ PL from the multilayer film is much higher than that of the monolayer film. The enhancement of Er³⁺ PL might be due to the energy transfer from Si-NCs to Er³⁺ions located around Si-NCs in the Er: Si: Al₂O₃ layers and Si: Al₂O₃ layers. Meanwhile, the multilayer film exhibits a nonmonotonic temperature dependence. Furthermore, the PL intensity of the multilayer film at RT is higher than that at 14K. These properties of the Er³⁺PL from the Er: SRA multilayer structures might provide good perspectives for the development of Er-doped waveguide amplifiers operating at high temperature.