In this study, hexagonal AlN (h-AlN) thin films were grown on a two-dimensional (2D)-WS₂/Al₂O₃ substrate by radio frequency–metalorganic molecular beam epitaxy at 800 °C. We examined the influence of various RF plasma powers on the synthesis and characterization of AlN/WS₂ heterostructures, as well as their properties, for optoelectronic applications. In-plane grazing incidence X-ray diffraction results indicated that the h-AlN thin films grown on 2D-WS₂/Al₂O₃(0001) are oriented along (100) and (110) planes, indicating epitaxial growth with orientation relationships between AlN(101̅0)//WS₂(101̅0)//Al₂O₃(112̅0) and AlN(112̅0)//WS₂(112̅0)//Al₂O₃(112̅0). The full width at half-maximum values of the AlN thin film at 300 W of RF power were measured to be 260 and 1400 arcsec for (0002) and (101̅0) reflections, respectively. Transmission electron microscopy images show that the AlN (0002) films can grow epitaxially with the WS₂/Al₂O₃ substrate and that the film structure is nearly stoichiometric in composition. In addition, the AlN film was measured to be approximately 50 nm thick. The AlN surface corresponds to the (0002) plane of AlN, and a direct measurement based on the lattice image yielded a lattice parameter of c = 4.98 Å. Additionally, the high-resolution cross-sectional transmission electron microscopy images show that the 50 nm-thick AlN film on WS₂ has relaxed lattice parameters and is a layered structure with an in-plane lattice match aligned with the underlying WS₂ lattice. This is evidence of domain-matching epitaxy with an atomic ratio of 7:7:8, demonstrating a commensurate match among AlN, WS₂, and Al₂O₃. These results will have a significant impact on the heteroepitaxy of high-quality thin AlN films with a WS₂ buffer and will facilitate the preparation of nitride-based optoelectronic devices at low growth temperatures.

中文翻译：

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h-AlN 和二维 WS2/c-Al2O3 之间 7:7:8 相当异质界面的范德华外延生长和表征

在本研究中，通过射频-金属有机分子束外延在800℃下在二维(2D)-WS ₂ /Al ₂ O _{3衬底上生长了六方AlN (h-AlN)薄膜。我们研究了不同射频等离子体功率对光电应用中 AlN/WS 2}异质结构的合成和表征及其性能的影响。_{面内掠入射X射线衍射结果表明，在2D-WS 2} /Al ₂ O ₃ (0001)上生长的h-AlN薄膜沿(100)和(110)面取向，表明外延生长具有取向关系介于 AlN(101̅0)//WS ₂ (101̅0)//Al ₂ O ₃ (112̅0) 和 AlN(112̅0)//WS ₂ (112̅0)//Al ₂ O ₃ (112̅0) 之间。在 300 W RF 功率下，对于 (0002) 和 (101̅0) 反射，AlN 薄膜的半峰全宽分别测量为 260 和 1400 弧秒。透射电子显微镜图像显示AlN(0002)薄膜可以与WS ₂ /Al ₂ O ₃衬底外延生长，并且薄膜结构的组成接近化学计量。另外，测量出AlN膜的厚度约为50nm。AlN 表面对应于 AlN 的 (0002) 面，基于晶格图像的直接测量得出的晶格参数为c = 4.98 Å。此外，高分辨率横截面透射电子显微镜图像显示，WS ₂上的50 nm厚的AlN薄膜具有松弛的晶格参数，并且是一种层状结构，其面内晶格匹配与下面的WS ₂晶格对齐。这是原子比为 7:7:8 的域匹配外延的证据，证明了 AlN、WS ₂和 Al ₂ O ₃之间的相当匹配。_{这些结果将对具有WS 2}缓冲剂的高质量AlN薄膜的异质外延产生重大影响，并将有助于在低生长温度下制备氮化物基光电器件。