Morphology control of epitaxial monolayer transition metal dichalcogenides
Morphology control of epitaxial monolayer transition metal dichalcogenides
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DOI：
10.1103/physrevmaterials.4.014003
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发表时间：
2020-01-15
影响因子：
3.4
通讯作者：
King, Philip D. C.
中科院分区：
文献类型：
--
作者：
Rajan, Akhil;Underwood, Kaycee;King, Philip D. C.
为了促进对过渡金属二硫化物（TMD）单层材料的基本认识和最终应用，必须发展高质量单层样品的合成能力。分子束外延（MBE）是制造高质量传统半导体外延膜的主要技术，然而，当应用于单层tmd的范德瓦尔斯生长时，通常只能产生小晶粒尺寸和次优形貌。本文采用MBE技术系统研究了吸附原子迁移率、生长速率和金属硫通量对NbSe2、VSe2和TiSe2生长的影响。通过这种方法，我们确定了控制tmd外延生长的关键驱动因素和影响因素，实现了生长化合物的四种不同形态。我们用它来确定制造高质量单层的最佳生长条件，最终实现迄今为止通过MBE生长实现的最大晶粒尺寸的单层tmd。
To advance fundamental understanding and ultimate application of transition-metal dichalcogenide (TMD) monolayers, it is essential to develop capabilities for the synthesis of high-quality single-layer samples. Molecular beam epitaxy (MBE), a leading technique for the fabrication of the highest-quality epitaxial films of conventional semiconductors has, however, typically yielded only small grain sizes and suboptimal morphologies when applied to the van der Waals growth of monolayer TMDs. Here, we present a systematic study on the influence of adatom mobility, growth rate, and metal:chalcogen flux on the growth of NbSe2, VSe2, and TiSe2 using MBE. Through this, we identify the key drivers and influence of the adatom kinetics that control the epitaxial growth of TMDs, realizing four distinct morphologies of the as-grown compounds. We use this to determine optimized growth conditions for the fabrication of high-quality monolayers, ultimately realizing the largest grain sizes of monolayer TMDs that have been achieved to date via MBE growth.