基于量子点阵列敏化的高效硅基近红外发光器件研究

Under condition of optical pumping, low-loss EDFLs and BDFLs have greatly stimulated the development of optical fiber communication technique, whereas no electrically pumped Er/Bi-related lasers have ever been demonstrated successfully until now due to extremely low conversion efficiency of electricity to light. Thus, the fully explored electrical pumping Er/Bi-related light source and greatly improved electroluminescence efficiency are still urgent issues for future development of integrated optoelectronic chip. During this project, we intends to select size-tunable metal oxide quantum dot arrays as sensitizers for improving electroluminescence efficiency of rare earth ions or transition metal ions by resonance energy transfer mechanisms. Based on the confined crystallization principle, the geometric parameters of quantum dot arrays will be adjusted as required. The tunneling efficiency of carriers will be further improved, meanwhile, the turn-on voltage of prototype device will be continuously decreased by hierarchical controls of hot-electron acceleration and impact ionization processed. Additionally, surficial microstructure antireflection and flip chip technologies will be developed for further improving the light extraction efficiency of prototype device. Furthermore, the carriers’ injection, drift, tunneling, capture, coupling, release, and recombination processes in transport layer will be elucidated in detail, respectively. With considerations of spectrum matching and exciton concentration distribution, the exciton absorption, resonance energy transfer, and luminescence enhancement mechanisms will be systematically evaluated through multi-physical field coupling simulation of metal oxide quantum dot arrays doped in silica thin films. This project will provide a solid theoretical and technical support for future design of Si-based near-infrared electrically pumped lasers.

在光泵浦下，低损耗的掺铒光纤激光器、掺铋光纤激光器已广泛应用于光通信等领域，然而在电泵浦下，由于低的光电转换效率，基于铒离子、铋离子的近红外激光器至今仍难实现。电泵浦效率低下成为制约集成光电芯片发展的关键问题之一。本项目拟采用一系列尺寸可控的金属氧化物量子点阵列作为敏化剂，利用共振能量转移机制提高铒离子、铋离子等发光中心的电致发光效率。其中，结合限制性晶化原理，优化阵列几何参数，实现对硅基薄膜中过热电子加速和碰撞离化过程的分层控制，有效提高载流子的隧穿效率、降低器件开启电压；尝试表面微结构减反技术与倒装芯片技术，提高光提取效率；阐明器件中载流子的注入、漂移、隧穿、俘获、耦合、释放、复合等输运机理；对量子点阵列进行多物理场耦合模拟，结合光谱响应匹配、激子浓度分布等因素，明确电泵浦下耦合体系中激子吸收、共振能量转移、发光增强等机理，为未来高效硅基电泵浦近红外激光器的实现提供理论依据和技术支撑。

硅基光电集成的关键技术之一是实现高效、稳定的硅基光源。其中稀土掺杂硅基薄膜电致发光材料与器件是实现高效硅基光源的重要研究途径。本项目拟通过磁控溅射、等离子体化学气相沉积等薄膜淀积工艺，结合限制性晶化原理，研制稀土掺杂富硅氧化硅、富硅氮化硅，硅氮氧等多种硅基薄膜；通过设计和构建电致发光原型器件，研究电泵浦下稀土敏化激发与热载流子碰撞离化激发等过程的发生条件与物理机制；通过能带工程、掺杂工程、缺陷工程，提高硅基薄膜中稀土离子的敏化激发效率，实现热载流子对稀土离子的高效碰撞离化激发，并探索避免能量背传递、俄歇复合等多种退激发过程的有效技术途径。在本项目中，通过量子点尺寸和数密度的有效控制，稀土铒离子的近红外特征发光强度提高了三个数量级。最优参数下的电致发光器件的开启电压低于4.5伏特，外量子发光效率达到0.7%和长达1000小时的工作时间，器件性能优于绝大多数现存的硅基近红外电致发光器件。