Despite the recent success of GeSn infrared lasers, the high lasing threshold currently limits their integration into practical applications. While structural defects in epitaxial GeSn layers have been identified as one of the major bottlenecks towards low-threshold GeSn lasers, the effect of defects on the lasing threshold has not been well studied yet. Herein, we experimentally demonstrate that the reduced defect density in a GeSn-on-insulator substrate improves the lasing threshold significantly. We first present a method of obtaining high-quality GeSn-on-insulator layers using low-temperature direct bonding and chemical–mechanical polishing. Low-temperature photoluminescence measurements reveal that the reduced defect density in GeSn-on-insulator leads to enhanced spontaneous emission and a reduced lasing threshold by $\sim 10$ times and $\sim 6$ times, respectively. Our result presents a new path towards pushing the performance of GeSn lasers to the limit.

中文翻译：

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绝缘体上 GeSn 衬底上的光泵浦低阈值微盘激光器，具有降低的缺陷密度

尽管 GeSn 红外激光器最近取得了成功，但高激光阈值目前限制了它们在实际应用中的集成。虽然外延 GeSn 层中的结构缺陷已被确定为低阈值 GeSn 激光器的主要瓶颈之一，但缺陷对激光阈值的影响尚未得到很好的研究。在此，我们通过实验证明，GeSn-on-insulator 衬底中降低的缺陷密度显着提高了激光阈值。我们首先提出了一种使用低温直接键合和化学机械抛光获得高质量绝缘体上 GeSn 层的方法。低温光致发光测量表明，绝缘体上 GeSn 中缺陷密度的降低导致自发发射增强和激光阈值降低$～10$次和$～6$次，分别。我们的结果为将 GeSn 激光器的性能推向极限提供了一条新途径。