The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi'an 710071, People's Republic of China.
Shaanxi Joint Key Laboratory of Graphene, Xidian University, Xi'an 710071, People's Republic of China.
Nanotechnology. 2023 May 9;34(29). doi: 10.1088/1361-6528/accc39.
The advantages of van der Waals epitaxial nitrides have become a research hot topic. It is worth noting that graphene plays an important role in the research of epitaxial AlN epitaxial layer. In this work, we demonstrate a method to obtain high-quality and low-dislocation AlN epitaxial layer by combining graphene and sputtered AlN as the nucleation layer on the C-sapphire substrate via metal organic chemical vapor deposition, and successfully fabricated a 277 nm AlGaN-based deep ultraviolet light emitting diode (DUV-LED) based on the obtained AlN epitaxial layer. The presence of graphene promotes the stress release of AlN. Compared with the AlN epitaxial layer directly grown on graphene/sapphire substrate, the exist of sputtered AlN/graphene nucleation layer facilitates most of the threading dislocations in AlN can annihilate each other in the range of about 100 nm. Thus, as grown AlN epitaxial layer shows the decreasing of the screw dislocation from 2.31 × 10to 2.08 × 10cmsignificantly. We manufacture an DUV-LED with 277 nm emission wavelength by using high-quality AlN films, which shows that magnitude of the leakage current is only on the order of nanoamperes and the forward turn on voltage is 3.5 V at room temperature. This study provides a meaningful strategy to achieve high-quality AlN film and high-performance DUV-LED.
范德华外延氮化物的优势已成为研究热点。值得注意的是，石墨烯在研究外延 AlN 外延层中起着重要作用。在这项工作中，我们通过金属有机化学气相沉积法，展示了一种在 C 蓝宝石衬底上结合石墨烯和溅射 AlN 作为形核层来获得高质量、低位错 AlN 外延层的方法，并成功地基于所获得的 AlN 外延层制造了 277nm 的基于 AlGaN 的深紫外发光二极管（DUV-LED）。石墨烯的存在促进了 AlN 的应力释放。与直接在石墨烯/蓝宝石衬底上生长的 AlN 外延层相比，溅射 AlN/石墨烯形核层的存在使得 AlN 中的大部分位错在约 100nm 的范围内相互湮灭。因此，所生长的 AlN 外延层的螺位错密度从 2.31×10^6cm^-2显著降低至 2.08×10^6cm^-2。我们使用高质量的 AlN 薄膜制造了具有 277nm 发射波长的 DUV-LED，其室温下的泄漏电流仅为数纳安量级，正向导通电压为 3.5V。这项研究为实现高质量 AlN 薄膜和高性能 DUV-LED 提供了有意义的策略。
