Ge $_{{1}-{x}}$ Sn_x alloy films with Sn contents of 3% and 10% were grown on Si wafers by low-temperature nonequilibrium molecular beam epitaxy. The thermostabilities of the GeSn films and photodetectors containing them were studied. No Sn segregation was observed in Ge_0.97Sn_0.03 films annealed below 750 °C. Conversely, Sn segregation occurred and Sn nanoparticles formed within the Ge_0.90Sn_0.10 films annealed above 400 °C. Upon increasing the annealing temperature to 750 °C, Sn particles were thermally driven and segregated on the surface of both Ge_0.97Sn_0.03 and Ge_0.90Sn_0.10 films. Photodetectors were fabricated based on the as-grown and annealed Ge_0.90Sn_0.10 films. Because of the decreased defect content of the Ge_0.90Sn_0.10 film after annealing, the dark current of the GeSn photodetectors decreased obviously and the responsivity of the devices increased. These results are fundamentally important for the applications of high-performance photodetectors and lasers based on GeSn alloys.

中文翻译：

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退火对 GeSn 合金和 GeSn 基光电探测器中 Sn 行为的影响

葛 $_{{1}-{x}}$ 锡_X通过低温非平衡分子束外延在Si晶片上生长Sn含量为3％和10％的合金薄膜。研究了 GeSn 薄膜和包含它们的光电探测器的热稳定性。在低于 750 °C 退火的Ge _0.97 Sn _0.03薄膜中没有观察到 Sn 偏析。相反，在 400 °C 以上退火的 Ge _0.90 Sn _0.10薄膜中会发生 Sn 偏析并形成 Sn 纳米颗粒。在将退火温度提高到 750 °C 后，Sn 颗粒被热驱动并在 Ge _0.97 Sn _0.03和 Ge _0.90 Sn _0.10薄膜的表面分离。基于生长和退火的 Ge 制造光电探测器_0.90 Sn _0.10薄膜。由于退火后Ge _0.90 Sn _0.10薄膜的缺陷含量降低，GeSn光电探测器的暗电流明显降低，器件的响应度增加。这些结果对于基于 GeSn 合金的高性能光电探测器和激光器的应用至关重要。