4TH International Congress on Technology - Engineering & SCIENCE - Kuala Lumpur - Malaysia (2017-08-05)

A Study Of Laser Cutting And Thinning MoS2 Using White Light Laser
Two-dimensional (2D) materials such as Molybdenum disulfide (MoS2) are emerging materials with a wide range of electrical and optical applications. Therefore, layer-dependent properties of MoS2 have been studied widely and confirm that a tunable band gap can be introduced for further possibility of many optoelectronic applications. Although mechanical and chemical exfoliation methods can be used to obtain high quality MoS2 few-layers, it is difficult to control in the thickness, shape, size, and position of the flakes limits their usefulness. Here, we propose one processing application by cutting and defining small pattern on MoS2 thin films using white light laser. The method is controllably thinning of multilayered MoS2, which is focused on the surface of the sample by using high power pulsed laser, then producing high heat on the sample surface, which instantly burns the sample surface and cuts out the desired pattern by this collimation. The sample cutting depth can be adjusted according to the output power of the laser by changing the different filters, and define the desired pattern through the moving of the x-y axis platform in the program developed. The fabricated MoS2 sample after processing is observed by optical microscopy (OM), scanning electron microscopy (SEM) and is discussed the relationship between the power and the depth with alpha step (α-step) for the purpose of proving our system. In order to obtain the semiconducting properties of MoS2, and to research the application after the cutting and thinning, we discovered the capacitance characteristic for the fabrication of 2D MoS2 film after cutting well-defined finger-like electrodes, through the capacitance-voltage measurement and impedance analysis. The feature may be employed in microwave applications because it arises particularly evidently at higher frequencies. So we have developed a laser system with white light pulse laser to cut and thin MoS2 film process. We can observe some obvious traces through the different functions using microscopy techniques. The thickness of MoS2 is controllable by adjusting white laser power. According to the experiments above, we proved that laser progress is reliable to produce the appropriate sample for the applications of MoS2. A series of experiments demonstrates that white laser could be used for cutting and even thinning, and applied for 2D semiconductors development to bring more gains.
Zheng-Sheng Chen, Tsung-Shine Ko, Der-Yuh Lin, Yu-Chung Chang, Ting-Zhong Dai