A low‐threshold, monolithically integrated laser on Si is considered a crucial missing ingredient in realizing efficient fully functional photonic‐integrated circuits (PICs). Owing to its compatibility with complementary metal‐semiconductor‐oxide (CMOS) processes, direct bandgap GeSn alloy has recently been studied intensively in hopes of making GeSn lasers the mainstream technology for PICs. However, the inevitable formation of harmful defects in GeSn directly grown on Si has thus far required the use of non‐monolithic approaches such as wafer bonding to obtain high‐quality GeSn layers, preventing the realization of practical, low‐threshold GeSn lasers. Here, ultra‐low threshold lasing in a monolithically‐grown, nearly‐defect‐free GeSn single‐crystal layer is demonstrated. The rapid melting growth method used in this study allows the fabrication of a compact, integrated laser that simultaneously achieves an ideal GeSn gain medium with built‐in tensile strain and an excellent GeSn optical cavity on an insulating layer. The measured threshold is ≈0.52 kW cm−2 under the optical pumping scheme at 10 K, which is the lowest among all the reported GeSn lasers. This work provides a new solution for building a truly CMOS‐compatible, monolithic laser that can complete the device library of the mature Si photonics foundries.

中文翻译：

---

利用快速熔融生长的单片集成超低阈值 GeSn on 绝缘体激光器


硅上的低阈值、单片集成激光器被认为是实现高效全功能光子集成电路 （PIC） 的关键缺失要素。由于其与互补金属-半导体-氧化物 （CMOS） 工艺的兼容性，直接带隙 GeSn 合金最近得到了深入研究，希望使 GeSn 激光器成为 PIC 的主流技术。然而，直接在硅上生长的 GeSn 中不可避免地会形成有害缺陷，迄今为止需要使用非单片方法（如晶圆键合）来获得高质量的 GeSn 层，从而阻碍了实用的低阈值 GeSn 激光器的实现。在这里，展示了单片生长、几乎无缺陷的 GeSn 单晶层中的超低阈值激光。本研究中使用的快速熔融生长方法可以制造一种紧凑的集成激光器，同时在绝缘层上实现具有内置拉伸应变和出色 GeSn 光腔的理想 GeSn 增益介质。在 10 K 的光泵浦方案下，测得的阈值为 ≈0.52 kW cm-2，这是所有报道的 GeSn 激光器中最低的。这项工作为构建真正兼容 CMOS 的单片激光器提供了一种新的解决方案，可以完成成熟的 Si 光子代工厂的器件库。