Defect engineering on MoS2 surface with argon ion bombardments and thermal annealing
Defect engineering on MoS2 surface with argon ion bombardments and thermal annealing
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DOI：
10.1016/j.apsusc.2020.147461
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发表时间：
2020-12
影响因子：
6.7
通讯作者：
Weigang Lu;B. Birmingham;Zhenrong Zhang
中科院分区：
文献类型：
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作者：
Weigang Lu;B. Birmingham;Zhenrong Zhang
已经开发了各种方法来生产MoS 2单层和多层。采用等离子体减薄和热减薄，逐层减薄工艺开发，以产生MoS 2单层和多层。然而，在这些过程中产生的减薄机制和缺陷的原子级的理解是不清楚的。利用超高真空扫描隧道显微镜（STM）研究了氩离子（Ar+）轰击和热退火对MoS 2块材表面结构的影响。Ar+轰击前后的STM图像显示，低能（50 eV）Ar+离子轰击MoS 2表面，可使表面的单个原子被去除，并使表面硫层破碎，在MoS 2表面形成单个硫空位点缺陷和原子坑。更高能量（100 eV）的Ar+离子可以穿透更深并且去除最顶部的MoS 2三层。在用500 eV的Ar+束轰击后，MoS 2表面表现为由1-3 nm纳米颗粒组成的颗粒状纳米结构。在热退火时，在650 °C下加热5分钟后，通过升华除去最顶部的硫原子，并且在较长的退火时间下观察到更深的原子升华，从而在MoS 2表面上产生粒状纳米结构。
Various approaches have been developed to produce MoS2monolayers and multilayers. Using plasma and thermal thinning, layer-by-layer thinning processes were developed to produce MoS2monolayer and multilayers. However, an atomic-level understanding of the thinning mechanism and defects created in these processes is not clear. In this paper, we studied the impact on surface structures of bulk MoS2by argon ion (Ar+) bombardments and thermal annealing using an ultra-high vacuum (UHV) scanning tunneling microscope (STM). The STM images obtained before and after Ar+bombardments show that low-energy (50 eV) Ar+ions can remove single atoms from the surface and fragment the top sulfur layer resulting in single sulfur vacancy point defects and atomic pits on the MoS2surface. Higher energy (100 eV) Ar+ions can penetrate deeper and remove the topmost MoS2trilayer. After bombardment with an Ar+beam of 500 eV, the MoS2surface appeared as granulated nanostructures consisting of 1–3 nm nanoparticles. Upon thermal annealing, topmost sulfur atoms were removed through sublimation after heating at 650 °C for 5 min and deeper atom sublimation was observed with longer annealing time, resulting in granulated nanostructures on the MoS2surface.