Wang Weixi, Ngo Éric, Bulkin Pavel, Zhang Zhengyu, Foldyna Martin, Roca I Cabarrocas Pere, Johnson Erik V, Maurice Jean-Luc
Laboratoire de Physique des Interfaces et Couches Minces, École Polytechnique, CNRS, IPParis, 91120 Palaiseau, France.
Laboratoire LuMIn, École Normale Supérieure Paris-Saclay, CentraleSupélec, Université Paris-Saclay, CNRS, 91190 Gif-sur-Yvette, France.
Nanomaterials (Basel). 2023 Jul 12;13(14):2061. doi: 10.3390/nano13142061.
We report silicon nanowire (SiNW) growth with a novel Cu-In bimetallic catalyst using a plasma-enhanced chemical vapor deposition (PECVD) method. We study the structure of the catalyst nanoparticles (NPs) throughout a two-step process that includes a hydrogen plasma pre-treatment at 200 °C and the SiNW growth itself in a hydrogen-silane plasma at 420 °C. We show that the H-plasma induces a coalescence of the Cu-rich cores of as-deposited thermally evaporated NPs that does not occur when the same annealing is applied without plasma. The SiNW growth process at 420 °C induces a phase transformation of the catalyst cores to CuIn; while a hydrogen plasma treatment at 420 °C without silane can lead to the formation of the CuIn phase. In situ transmission electron microscopy experiments show that the SiNWs synthesis with Cu-In bimetallic catalyst NPs follows an essentially vapor-solid-solid process. By adjusting the catalyst composition, we manage to obtain small-diameter SiNWs-below 10 nm-among which we observe the metastable hexagonal diamond phase of Si, which is predicted to have a direct bandgap.
我们报道了使用等离子体增强化学气相沉积（PECVD）方法，通过一种新型的铜-铟双金属催化剂生长硅纳米线（SiNW）。我们在一个两步过程中研究了催化剂纳米颗粒（NP）的结构，该过程包括在200°C下进行氢等离子体预处理以及在420°C的氢-硅烷等离子体中进行SiNW生长本身。我们表明，氢等离子体诱导了沉积态热蒸发NP中富铜核的聚结，而在没有等离子体的情况下进行相同退火时不会发生这种聚结。420°C下的SiNW生长过程诱导催化剂核转变为CuIn相；而在420°C下无硅烷的氢等离子体处理可导致CuIn相的形成。原位透射电子显微镜实验表明，用铜-铟双金属催化剂NP合成SiNW遵循基本的气-固-固过程。通过调整催化剂组成，我们成功获得了直径小于10nm的小直径SiNW，在其中我们观察到了硅的亚稳六方金刚石相，预计该相具有直接带隙。
