突破间接带局限 创新Si基激光器

Breakthrough of the indirect band-gap limitation for the realization of Si-based laser devices

Si基高效发光与受激光发射是Si基光子学突破性发展的关键课题 ,它的实现对Si基微电子学的发展有深远的重大意义 .由于受到天然Si材料间接带能带结构的限制 ,Si材料的发光效率极低 ,更谈不上可实现受激光发射 ,人工改性就成为当代研究、开拓的主要途径 .新的Si基直接带体材料 (如 β -FeSi2 等 )的探索 ,Ge/Si量子阱、超晶格、量子点的能带工程介观改性 ,子带发光跃迁的探索 ,异类元素插入短周期超晶格中的化学键改性 ,以及SiO2 高浓度nc-Si的生成和高激活度稀土离子的掺入发光等已开展了多途径的研究 ,不同程度上取得了重要的进展 ,一种MIS结构电子隧道注入高效发光器件已在SiO2 :REMOS结构中实现 .运用激光器件物理的深入设计和新的器件技术的引入 ,可以预计本世纪初叶 ,对实现Si基激光器的奢望将会成为现实 ,无疑它对Si基光子学。

The realization of high efficiency luminescence and stimulated emission is of great significance for the development of Si-based photonics and advanced Si-based micro-optoelectronics. However, the luminescencet efficiency of Si is too low, even barely enough to realize stimulated emission due to the indirect energy band structure. Therefore, searching for ways to artificially modify the original Si material properties is an important project.Many efforts have been made towards this target with different degrees of success, including research on luminescence from β-FeSi 2, Ge/Si multi-quantum wells, dots and supper-lattices, the radiative transition between subband levels in SiGe/Si quantum wells, luminescence from nano-scale Si (nc-Si) in SiO 2, rare-earth (RE) ion doped SiO 2, and novel Si-based materials with direct band-gaps and modified chemical bonds. An effective luminescent device with an SiO 2:RE active medium and metal-insulator-semiconductor (MIS) structure has been successfully fabricated, and it is expected that a Si-based laser device will be realized within this decade through precise design of the device structure and application of new technologies. This would be a great contribution to the development of Si-based photonics and integrated optoelectronics.