AI 中文总结
研究在硅上集成近红外VCSEL的瓶颈问题，采用两步生长策略直接外延集成，有效抑制缺陷传播，实现高反射率DBR结构均匀性，展示了低阈值电流的VCSEL，为硅基光子系统集成提供概念验证和可行途径。
AI 中文摘要
紧凑激光源与硅的单片集成是硅光子学可扩展发展的关键瓶颈。特别是，在硅上直接外延生长近红外垂直腔面发射激光器（VCSEL）长期受阻，因为有源区需低晶体缺陷密度且分布布拉格反射镜（DBR）镜需光滑界面，这对实现高腔品质因数和低激射阈值至关重要。本文报道了采用两步生长策略在硅衬底上直接外延集成近红外VCSEL，该策略能抑制缺陷传播并保持镜界面陡度。此方法可有效限制位错进入有源区并确保高反射率DBR的结构均匀性。结构和光学表征显示高质量外延堆叠，使激光性能与通常在GaAs衬底上生长的VCSEL相当。首次展示了在硅片上直接生长的VCSEL阈值电流仅几毫安。这些结果为高性能VCSEL与硅平台的单片集成提供了决定性概念验证，并为全集成、低成本硅基光子系统开辟了可行途径。
英文摘要
The monolithic integration of compact laser sources onto silicon remains a critical bottleneck for the scalable development of silicon photonics. In particular, the direct epitaxial growth of near-infrared vertical-cavity surface-emitting lasers (VCSELs) on silicon has long been hindered by the simultaneous requirements of low crystalline defect density in the active region and smooth interfaces in the distributed Bragg reflector (DBR) mirrors, both essential to achieving high cavity quality factors and low lasing thresholds. Here, we report the direct epitaxial integration of near-infrared VCSELs on silicon substrates using a two-step growth strategy specifically designed to suppress defect propagation while preserving mirror interface abruptness. This approach enables effective confinement of threading dislocations away from the active region and ensures high-reflectivity DBRs with excellent structural uniformity. Structural and optical characterizations reveal an epitaxial stack of high crystalline quality, leading to laser performance comparable to VCSELs commonly grown on GaAs substrates. We demonstrate, for the first time, directly grown VCSELs on silicon wafers exhibiting threshold currents of only a few milliamperes. These results establish a decisive proof of concept for the monolithic integration of good-performance VCSELs onto silicon platforms and open a viable pathway toward fully integrated, low-cost silicon-based photonic systems.
