Laser-Induced Particle Adsorption on Atomically Thin MoS2

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• 作者：Bien Cuong Tran Khac ; Ki-Joon Jeon ; Seung Tae Choi ; Yong Soo Kim ; Frank W. DelRio ; Koo-Hyun Chung
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 10, 2016
• 年：2016
• 卷：8
• 期：5
• 页码：2974-2984
• 全文大小：859K
• ISSN：1944-8252

文摘

Atomically thin molybdenum disulfide (MoS₂) shows great potential for use in nanodevices because of its remarkable electronic, optoelectronic, and mechanical properties. These material properties are often dependent on the thickness or the number of layers, and hence Raman spectroscopy is widely used to characterize the thickness of atomically thin MoS₂ due to the sensitivity of the vibrational spectrum to thickness. However, the lasers used in Raman spectroscopy can increase the local surface temperature and eventually damage the upper layers of the MoS₂, thereby changing the aforementioned material properties. In this work, the effects of lasers on the topography and material properties of atomically thin MoS₂ were systematically investigated using Raman spectroscopy and atomic force microscopy. In detail, friction force microscopy was used to study the friction characteristics of atomically thin MoS₂ as a function of laser powers from 0.5 to 20 mW and number of layers from 1 to 3. It was found that particles formed on the top surface of the atomically thin MoS₂ due to laser-induced thermal effects. The degree of particle formation increased as the laser power increased, prior to the thinning of the atomically thin MoS₂. In addition, the degree of particle formation increased as the number of MoS₂ layers increased, which suggests that the thermal behavior of the supported MoS₂ may differ depending on the number of layers. The particles likely originated from the atmosphere due to laser-induced heating, but could be eliminated via appropriate laser powers and exposure times, which were determined experimentally. The outcomes of this work indicate that thermal management is crucial in the design of reliable nanoscale devices based on atomically thin MoS₂.