Molecular beam epitaxy of two-dimensional (2D) GaTe nanostructures on GaAs(001) substrates has been reported in this study. A trade-off between growth temperature and growth time (thickness) is a prerequisite for governing the crystal morphology of 2D GaTe materials from 2D epitaxial thin films to pseudo-one-dimensional (1D)/2D nanostructures (including nanorods, nanotriangles, and nanodendrites). Importantly, through real-time azimuthal reflection high-energy electron diffraction, a coexistence of hexagonal-GaTe (h-GaTe) and monoclinic-GaTe (m-GaTe) phases in the film was explored, corresponding to formation of lateral h/m-GaTe heterophase homojunctions. In addition, we found that utilizing a GaN/sapphire platform instead of the GaAs(001) substrate promotes formation of a single-phase h-GaTe in the thin film, which could be due to the surface-symmetry matching between the GaN/sapphire platform and the h-GaTe phase. Together with observing an asymmetric emission broad band of ∼1.76 eV that comes from the pseudo-1D m-GaTe phase, we provide convincing evidence that the emission feature located at 1.46 eV originates from the near-band-edge emission of the 2D h-GaTe epitaxial thin film. These results are meaningful in providing practical schemes to control the crystal phases of 2D GaTe materials and realize either hexagonal–monoclinic heterophase lateral homojunctions or single-phase h-GaTe epitaxial thin films on a wafer scale for future functional (opto)electronic devices, especially for near-infrared photodetectors.

中文翻译：

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GaAs(001) 衬底上二维 GaTe 纳米结构的分子束外延：对近红外光电检测的影响

本研究报道了 GaAs(001) 衬底上二维 (2D) GaTe 纳米结构的分子束外延。生长温度和生长时间（厚度）之间的权衡是控制从 2D 外延薄膜到伪一维 (1D)/2D 纳米结构（包括纳米棒、纳米三角形和纳米枝晶）的 2D GaTe 材料晶体形态的先决条件）。重要的是，通过实时方位反射高能电子衍射，探索了六方-GaTe (h-GaTe) 和单斜-GaTe (m-GaTe) 相在薄膜中的共存，对应于横向 h/m- GaTe异相同质结。此外，我们发现利用 GaN/蓝宝石平台代替 GaAs(001) 衬底促进了薄膜中单相 h-GaTe 的形成，这可能是由于 GaN/蓝宝石平台和 h-GaTe 相之间的表面对称匹配。连同观察到来自伪 1D m-GaTe 相的~1.76 eV 的不对称发射宽带，我们提供了令人信服的证据，表明位于 1.46 eV 的发射特征源自 2D h-的近带边缘发射。氮化镓外延薄膜。这些结果对于提供实用的方案来控制 2D GaTe 材料的晶相和实现六方单斜异相横向同质结或单相 h-GaTe 外延薄膜在晶片规模上用于未来的功能（光）电子器件具有重要意义，尤其是用于近红外光电探测器。76 eV 来自伪 1D m-GaTe 相，我们提供了令人信服的证据，表明位于 1.46 eV 的发射特征源自 2D h-GaTe 外延薄膜的近带边缘发射。这些结果对于提供实用的方案来控制 2D GaTe 材料的晶相和实现六方单斜异相横向同质结或单相 h-GaTe 外延薄膜在晶片规模上用于未来的功能（光）电子器件具有重要意义，尤其是用于近红外光电探测器。76 eV 来自伪 1D m-GaTe 相，我们提供了令人信服的证据，表明位于 1.46 eV 的发射特征源自 2D h-GaTe 外延薄膜的近带边缘发射。这些结果对于提供实用的方案来控制 2D GaTe 材料的晶相和实现六方单斜异相横向同质结或单相 h-GaTe 外延薄膜在晶片规模上用于未来的功能（光）电子器件具有重要意义，尤其是用于近红外光电探测器。