Payne Anthony J R, Jr Neubi F Xavier, Tamtögl Anton, Sacchi Marco
School of Chemistry and Chemical Engineering, University of Surrey, GU2 7XH, Guildford, UK.
Institute of Experimental Physics, Graz University of Technology, Graz, 8010, Austria.
Small. 2025 Mar;21(10):e2405404. doi: 10.1002/smll.202405404. Epub 2025 Jan 5.
Understanding the chemical and physical mechanisms at play in 2D materials growth is critical for effective process development of methods such as chemical vapor deposition (CVD) as a toolbox for processing more complex nanostructures and 2D materials. A combination of density functional theory and microkinetic modeling is employed to comprehensively investigate the reaction mechanism governing the epitaxial growth of hexagonal boron nitride (hBN) on Ru(0001) from borazine. This analysis encompasses four key stages prior to the formation of the complete hBN overlayer: (i) adsorption, diffusion and deprotonation of borazine, (ii) dimerization and microkinetic modeling (iii) stability of larger borazine polymers and (iv) formation of nanoporous intermediates. In doing so, the exact deprotonation sequence is followed for the first time, illustrating its crucial role for the formation of nanostructures. These findings not only provide insights into the epitaxial growth of hBN and the stability of intermediate overlayers, which are strongly dependent on surface temperature and the amount of precursor exposures, they offer also crucial guidance for producing high-quality hBN monolayers with regular patterns or functionalisation. Importantly, these results align with experimental data and provide a detailed model which explains temperature-dependent, in-situ surface measurements during hBN growth on Ru and other substrates.
了解二维材料生长过程中所涉及的化学和物理机制，对于诸如化学气相沉积（CVD）等方法的有效工艺开发至关重要，这些方法可作为加工更复杂纳米结构和二维材料的工具箱。采用密度泛函理论和微观动力学模型相结合的方法，全面研究了硼嗪在Ru(0001)上外延生长六方氮化硼（hBN）的反应机理。该分析涵盖了完整hBN覆盖层形成之前的四个关键阶段：（i）硼嗪的吸附、扩散和去质子化，（ii）二聚化和微观动力学模型，（iii）较大硼嗪聚合物的稳定性，以及（iv）纳米多孔中间体的形成。在此过程中，首次追踪了确切的去质子化顺序，阐明了其在纳米结构形成中的关键作用。这些发现不仅深入了解了hBN的外延生长以及中间覆盖层的稳定性，它们强烈依赖于表面温度和前驱体暴露量，还为制备具有规则图案或功能化的高质量hBN单层提供了关键指导。重要的是，这些结果与实验数据一致，并提供了一个详细的模型，解释了在Ru和其他衬底上hBN生长过程中与温度相关的原位表面测量结果。
