IHP, Im Technologiepark 25, D-15236 Frankfurt (Oder), Germany.
Nanotechnology. 2018 Oct 12;29(41):415702. doi: 10.1088/1361-6528/aad626. Epub 2018 Jul 26.
We investigate the distribution of Sn in GeSn nano-heteroepitaxial clusters deposited at temperatures well exceeding the eutectic temperature of the GeSn system. The 600 °C molecular beam epitaxy on Si-patterned substrates results in the selective growth of GeSn nano-clusters having a 1.4 ± 0.5 at% Sn content. These nano-clusters feature Sn droplets on their faceted surfaces. The subsequent deposition of a thin Ge cap layer induced the incorporation of the Sn atoms segregated on the surface in a thin layer wetting the nano-dots surface with 8 ± 0.5 at% Sn. The presence of this wetting layer is associated with a relatively strong photoluminescence emission that we attribute to the direct recombination occurring in the GeSn nano-dots outer region.
我们研究了在远高于 GeSn 体系共晶温度的温度下沉积的 GeSn 纳米异质外延团簇中 Sn 的分布。在 Si 图案化衬底上进行的 600°C 分子束外延导致具有 1.4±0.5 at% Sn 含量的 GeSn 纳米团簇的选择性生长。这些纳米团簇在其有面的表面上具有 Sn 液滴。随后沉积一层薄的 Ge 帽层，促使表面上分离的 Sn 原子掺入，在纳米点表面上形成一层薄的润湿层，Sn 含量为 8±0.5 at%。这种润湿层的存在与相对较强的光致发光发射相关，我们将其归因于发生在 GeSn 纳米点外区的直接复合。
