Sb₂Se₃ thin film is an emerging photon absorber used in solar cells. We report the study of surface and interface structures of Sb₂Se₃(1 2 0) film grown on mica substrate by a high-rate vapor transport method. The interface epitaxial relationship between Sb₂Se₃ and mica examined by the cross- sectional TEM images and diffraction patterns along the [0 0 1] and [10]$\overline{2}$ directions of Sb₂Se₃ reveal a rectangular structure with lengths of 4.03 ± 0.1 Å and 5.29 ± 0.1 Å, consistent with the [1 2 0] out-of-plane direction of Sb₂Se₃ bulk lattice parameters. In contrast, the two-dimensional reciprocal space map (2D map) constructed from azimuthal reflection high-energy electron diffraction (ARHEED) patterns from the surface exhibits a decorated hexagonal structure. This surface structure emerges from six epitaxial orientation domains/rods and each domain has a rectangular unit mesh of 3.94 ± 0.09 Å and 26.95 ± 1.16 Å along the [0 0 1] and [10]$\overline{2}$ directions. The 26.95 Å is consistent with the unit mesh of the outermost layer of the Sb₂Se₃(1 2 0) domains/rods. Our 2D map reveals surface information that are not easily observed by other diffraction techniques.

Sb ₂ Se ₃薄膜是一种用于太阳能电池的新兴光子吸收剂。我们报告了通过高速蒸汽传输方法在云母衬底上生长的 Sb ₂ Se ₃ (1  2  0) 膜的表面和界面结构的研究。通过截面 TEM 图像和沿 [0 0 1] 和 [10] 的衍射图检查Sb ₂ Se ₃和云母之间的界面外延关系  $\overline{2}$Sb ₂ Se _{3 的}方向显示矩形结构，长度为 4.03 ± 0.1 Å 和 5.29 ± 0.1 Å，与Sb ₂ Se ₃体晶格参数的 [1  2  0] 面外方向一致。相比之下，由表面的方位反射高能电子衍射 (ARHEED) 图案构建的二维倒易空间图 (2D 地图) 显示出装饰的六边形结构。这种表面结构来自六个外延取向域/棒，每个域沿 [0 0 1] 和 [10]具有 3.94 ± 0.09 Å 和 26.95 ± 1.16 Å 的矩形单元网格  $\overline{2}$方向。26.95 Å 与 Sb ₂ Se ₃ (1  2  0) 域/棒最外层的单位网格一致。我们的 2D 地图揭示了其他衍射技术不容易观察到的表面信息。