Hijazi Hadi, Zeghouane Mohammed, Bassani Franck, Gentile Pascal, Salem Bassem, Dubrovskii Vladimir G
ITMO University, Kronverkskiy pr. 49, 197101, St. Petersburg, Russia.
Nanotechnology. 2020 Oct 2;31(40):405602. doi: 10.1088/1361-6528/ab99f6. Epub 2020 Jun 5.
It is well-known that the chemical potential which drives the vapor-liquid-solid growth of semiconductor nanowires is strongly affected by the liquid phase composition. Here, we investigate theoretically how the droplet composition influences the nucleation of Au-catalyzed GeSn nanowires on Ge(111) and Si(111) substrates. We compare the chemical potentials in an Au-Ge-Sn catalyst droplet before and after adding Ga and/or Si atoms. It is found that the presence of these atoms enhances the nucleation rate of nanowires on both substrates. Theoretical results are compared to experimental data on GeSn nanowires grown in a hot-wall reduced pressure chemical vapor deposition reactor. It is shown that the intentional addition of Ga in the de-wetting step improves the uniformity of the nanowire dimensions and yields higher density of nanowires over Ge(111) substrates. The nanowire growth on Si(111) substrate occurs only when Ga and/or Si are added to Au droplets. These results show that controlling the composition of the catalyst droplet is crucial for improving the quality of GeSn nanowires.
众所周知，驱动半导体纳米线气-液-固生长的化学势会受到液相组成的强烈影响。在此，我们从理论上研究了液滴组成如何影响在Ge(111)和Si(111)衬底上金催化的GeSn纳米线的成核过程。我们比较了添加Ga和/或Si原子前后Au-Ge-Sn催化剂液滴中的化学势。结果发现，这些原子的存在提高了两种衬底上纳米线的成核速率。将理论结果与在热壁减压化学气相沉积反应器中生长的GeSn纳米线的实验数据进行了比较。结果表明，在去湿步骤中有意添加Ga可改善纳米线尺寸的均匀性，并在Ge(111)衬底上产生更高密度的纳米线。仅当将Ga和/或Si添加到金液滴中时，才会在Si(111)衬底上生长纳米线。这些结果表明，控制催化剂液滴的组成对于提高GeSn纳米线的质量至关重要。
