蓝宝石侧hBN的形成：堆叠Ni--Cr/硼/蓝宝石构型中Ni--Cr介导生长的作用：硼供给的影响

中文摘要 AI 辅助

金属介导生长为高质量六方氮化硼（hBN）提供了有效途径，但金属上hBN的形成并不必然保证相邻介电基底上hBN的形成。在此，我们通过垂直堆叠的Ni--Cr/硼/蓝宝石构型，在1550°C、常压下，固定Ni:Cr = 8:2并改变相对硼供给量，研究了这一区别。在整个研究的Alloy:B范围内，拉曼光谱在暴露于气体的合金表面检测到hBN，而蓝宝石侧hBN仅在较高的相对硼供给量（Alloy:B = 24:1和18:1）下出现，这通过拉曼光谱和XRD得到确认。当硼供给量从24:1增加到18:1时，hBN（002）反射进一步变窄，对应的表观c轴相干长度从约86 nm增加到143 nm。仅在较高硼条件下还出现了额外的晶体反射。这些结果确定硼供给是控制从合金侧hBN形成到蓝宝石侧hBN同时生长的关键参数。一旦形成，蓝宝石侧hBN出现在显著重构且化学改性的富Al/O蓝宝石环境中，而非完整基底上的均匀薄膜。据我们所知，本研究首次证明了通过Ni--Cr介导生长成功形成蓝宝石侧hBN。

英文摘要

Metal-mediated growth provides an effective route to high-quality hexagonal boron nitride (hBN), but hBN formation on the metal does not necessarily ensure hBN formation on an adjoining dielectric substrate. Here, we investigate this distinction using a vertically stacked Ni--Cr/boron/sapphire configuration operated at 1550~$^\circ$C under atmospheric pressure, with the relative boron supply varied at fixed Ni:Cr = 8:2. hBN is detected by Raman spectroscopy on the gas-exposed alloy surface throughout the investigated Alloy:B range, whereas sapphire-side hBN appears only at the higher relative boron supplies of Alloy:B = 24:1 and 18:1, as confirmed by both Raman spectroscopy and XRD. The hBN (002) reflection further narrows as the boron supply increases from 24:1 to 18:1, corresponding to an increase in the apparent c-axis coherent length from approximately 86 to 143~nm. Additional crystalline reflections also emerge only under these higher-boron conditions. These results identify boron supply as a key parameter governing the transition from alloy-side hBN formation to concurrent sapphire-side hBN growth. Once formed, sapphire-side hBN occurs within a substantially reconstructed and chemically modified Al/O-rich sapphire environment rather than as a uniform film on an intact substrate. To our knowledge, this study provides the first demonstration of successful sapphire-side hBN formation by Ni--Cr-mediated growth.

发表机构

• Kyung Hee University（庆熙大学）
• University of Seoul（首尔大学）
• Yonsei University（延世大学）

机构由 AI 辅助整理，请以论文原文为准。