46
views
0
recommends
+1 Recommend
1 collections
    1
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Friction characteristics of mechanically exfoliated and CVD- grown single-layer MoS 2

      research-article

      Read this article at

      ScienceOpenPublisher
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          In this work, the friction characteristics of single-layer MoS 2 prepared with chemical vapor deposition (CVD) at three different temperatures were quantitatively investigated and compared to those of single-layer MoS 2 prepared using mechanical exfoliation. The surface and crystalline qualities of the MoS 2 specimens were characterized using an optical microscope, atomic force microscope (AFM), and Raman spectroscopy. The surfaces of the MoS 2 specimens were generally flat and smooth. However, the Raman data showed that the crystalline qualities of CVD-grown single-layer MoS 2 at 800  °C and 850  °C were relatively similar to those of mechanically exfoliated MoS 2 whereas the crystalline quality of the CVD-grown single-layer MoS 2 at 900  °C was lower. The CVD-grown single-layer MoS 2 exhibited higher friction than mechanically exfoliated single-layer MoS 2, which might be related to the crystalline imperfections in the CVD-grown MoS 2. In addition, the friction of CVD-grown single-layer MoS 2 increased as the CVD growth temperature increased. In terms of tribological properties, 800  °C was the optimal temperature for the CVD process used in this work. Furthermore, it was observed that the friction at the grain boundary was significantly larger than that at the grain, potentially due to defects at the grain boundary. This result indicates that the temperature used during CVD should be optimized considering the grain size to achieve low friction characteristics. The outcomes of this work will be useful for understanding the intrinsic friction characteristics of single-layer MoS 2 and elucidating the feasibility of single-layer MoS 2 as protective or lubricant layers for micro- and nano-devices.

          Most cited references44

          • Record: found
          • Abstract: found
          • Article: not found

          Anomalous lattice vibrations of single- and few-layer MoS2.

          Molybdenum disulfide (MoS(2)) of single- and few-layer thickness was exfoliated on SiO(2)/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic force microscopy. Two Raman modes, E(1)(2g) and A(1g), exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the three-dimensional to the two-dimensional regime.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Stretching and breaking of ultrathin MoS2.

            We report on measurements of the stiffness and breaking strength of monolayer MoS(2), a new semiconducting analogue of graphene. Single and bilayer MoS(2) is exfoliated from bulk and transferred to a substrate containing an array of microfabricated circular holes. The resulting suspended, free-standing membranes are deformed and eventually broken using an atomic force microscope. We find that the in-plane stiffness of monolayer MoS(2) is 180 ± 60 Nm(-1), corresponding to an effective Young's modulus of 270 ± 100 GPa, which is comparable to that of steel. Breaking occurs at an effective strain between 6 and 11% with the average breaking strength of 15 ± 3 Nm(-1) (23 GPa). The strength of strongest monolayer membranes is 11% of its Young's modulus, corresponding to the upper theoretical limit which indicates that the material can be highly crystalline and almost defect-free. Our results show that monolayer MoS(2) could be suitable for a variety of applications such as reinforcing elements in composites and for fabrication of flexible electronic devices.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Fabrication of single- and multilayer MoS2 film-based field-effect transistors for sensing NO at room temperature.

              Single- and multilayer MoS(2) films are deposited onto Si/SiO(2) using the mechanical exfoliation technique. The films were then used for the fabrication of field-effect transistors (FETs). These FET devices can be used as gas sensors to detect nitrous oxide (NO). Although the single-layer MoS(2) device shows a rapid response after exposure to NO, the current was found to be unstable. The two-, three-, and four-layer MoS(2) devices show both stable and sensitive responses to NO down to a concentration of 0.8 ppm. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
                Bookmark

                Author and article information

                Journal
                Tsinghua Science and Technology
                Friction
                Tsinghua University Press (Xueyuan Building, Tsinghua University, Beijing 100084, China )
                2223-7690
                05 December 2018
                : 06
                : 04
                : 395-406 (pp. )
                Affiliations
                [ 1 ] School of Mechanical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
                [ 2 ] Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, Republic of Korea
                Author notes
                * Corresponding author: Koo-Hyun CHUNG, E-mail: khchung@ 123456ulsan.ac.kr

                Dinh Le Cao KY. He received his M.S. degree in mechanical engineering in 2010 from University of Technology, Ho Chi Minh City, Vietnam. He is currently pursuing his PhD degree in the Tribology and Surface Engineering Laboratory at University of Ulsan, Republic of Korea. His research interests include fundamental understanding of friction characteristics of nanomaterials from experiments and molecular dynamics simulation.

                Bien-Cuong TRAN KHAC. He received his M.S. degree in mechanical engineering in 2014 from University of Ulsan, Republic of Korea. He is currently pursuing his PhD degree in the Tribology and Surface Engineering Laboratory at the same university. His research interests include tribology and surface damage characteristics of atomically thin (2D) materials.

                Chinh Tam LE. He received his B.S. degree in material science in 2012 from Ho Chi Minh University of Natural Science in Vietnam. After then, he joined the Semiconductor Device Research Laboratory from 2013 and is currently the PhD student in University of Ulsan, Republic of Korea. His interest research is synthesis and optical characterization of monolayer transition metal dichalcogenides MX2.

                Yong Soo KIM. He received his M.S. and PhD degrees in physics from Seoul National University, Republic of Korea in 1993 and 1998, respectively. After then, he was a senior and principle researcher at R&D division, SK-Hynix Inc. He joined the Department of Physics at University of Ulsan, South Korea from 2008. His current position is associate professor, chair of physics department and director of human resource center for novel materials research experts (BK21+ program). His research interest includes organic- inorganic hybrid solar cell, 2-D layer materials relating optoelectronic device, especially transitional metal dichalcogenide growth and its optical characteristics.

                Koo-Hyun CHUNG. He received his M.S. and PhD degrees in mechanical engineering from Yonsei University, Republic of Korea, in 1997 and 2005, respectively. His current position is an associate professor at the School of Mechanical Engineering, University of Ulsan, South Korea. His research areas cover tribology, micro/nano tribology, adhesion, surface engineering, molecular dynamics simulation, as well as themes relating to material science.

                Article
                2223-7690-06-04-395
                10.1007/s40544-017-0172-8
                0bafeb09-c0bb-4368-9275-55f77f0a7871
                Copyright @ 2018

                © The author(s) 2017. This article is published with open access at Springerlink.com

                Open Access: The articles published in this journal are distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

                History
                : 17 April 2017
                : 06 June 2017
                : 07 June 2017
                Page count
                Figures: 5, Tables: 0, References: 52, Pages: 12
                Categories
                Research Article

                Materials technology,Materials properties,Thin films & surfaces,Mechanical engineering
                atomic force microscope,friction, mechanical exfoliation,MoS2 ,chemical vapor deposition,grain boundary

                Comments

                Comment on this article