Rotationally aligned hexagonal boron nitride on sapphire by high-temperature molecular beam epitaxy
Rotationally aligned hexagonal boron nitride on sapphire by high-temperature molecular beam epitaxy
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DOI：
10.1103/physrevmaterials.3.064001
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发表时间：
2019-06
影响因子：
3.4
通讯作者：
R. Page;Yongjin Cho;J. Casamento;S. Rouvimov;H. Xing;D. Jena
中科院分区：
文献类型：
--
作者：
R. Page;Yongjin Cho;J. Casamento;S. Rouvimov;H. Xing;D. Jena
采用超高温分子束外延（MBE）技术在蓝宝石衬底上生长了六方氮化硼（hBN）薄膜。已经探索了宽范围的衬底温度和硼通量，揭示了高结晶质量的hBN层在高衬底温度（> 1600 ℃）和低硼通量（10 - 8托束当量压力）下生长。原位反射高能电子衍射（RHEED）结果表明，生长的hBN层具有60 °旋转对称性，hBN的轴与蓝宝石衬底的轴平行。不同于粗糙，多晶薄膜先前报道，原子力显微镜（AFM）和透射电子显微镜（TEM）表征这些薄膜表现出光滑，分层，几纳米hBN薄膜的氮化蓝宝石衬底上。这种通过分子束外延实现高质量hBN生长的示范是将其整合到现有外延生长平台、应用和技术中的一步。
Hexagonal boron nitride (hBN) has been grown on sapphire substrates by ultra-high temperature molecular beam epitaxy (MBE). A wide range of substrate temperatures and boron fluxes have been explored, revealing that high crystalline quality hBN layers are grown at high substrate temperatures, $>$1600$^\circ$C, and low boron fluxes, $\sim1\times10^{-8}$ Torr beam equivalent pressure. \emph{In-situ} reflection high energy electron diffraction (RHEED) revealed the growth of hBN layers with $60^\circ$ rotational symmetry and the $[11\bar20]$ axis of hBN parallel to the $[1\bar100]$ axis of the sapphire substrate. Unlike the rough, polycrystalline films previously reported, atomic force microscopy (AFM) and transmission electron microscopy (TEM) characterization of these films demonstrate smooth, layered, few-nanometer hBN films on a nitridated sapphire substrate. This demonstration of high-quality hBN growth by MBE is a step towards its integration into existing epitaxial growth platforms, applications, and technologies.