Journal articles: 'MoS2 characterization'

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Withanage, Sajeevi S., Mike Lopez, Wasee Sameen, Vanessa Charles, and Saiful I. Khondaker. "Elucidation of the growth mechanism of MoS2 during the CVD process." MRS Advances 4, no. 10 (December 26, 2018): 581–86. http://dx.doi.org/10.1557/adv.2018.660.

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ABSTRACTChemical vapor deposition (CVD) growth of two-dimensional molybdenum disulfide (MoS2) using molybdenum trioxide (MoO3) and sulfur (S) powder often results in intermediate molybdenum oxy-sulfide (MoOS2) species along with MoS2 due to a lack of control over the vapor pressure required for the clean growth. Much effort has been devoted in understanding and controlling of these intermediate MoOS2 specifies. Here, we show that with a second step sulfurization at moderate temperatures, these MoOS2 crystals can be transformed to monolayer MoS2 crystals. Scanning electron microscopy, Raman and photoluminescence spectroscopy and atomic force microscopy characterization carried out before and after re-sulfurization confirm the monolayer MoS2 growth via this route. This study shows that MoOS2 formed at the intermediate state can be successfully recycled to MoS2.

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Zhang, Xian. "Characterization of Layer Number of Two-Dimensional Transition Metal Diselenide Semiconducting Devices Using Si-Peak Analysis." Advances in Materials Science and Engineering 2019 (September 10, 2019): 1–7. http://dx.doi.org/10.1155/2019/7865698.

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Atomically thin materials such as semiconducting transition metal diselenide materials, like molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2), have received intensive interests in recent years due to their unique electronic structure, bandgap engineering, ambipolar behavior, and optical properties and have motivated investigations for the next-generation semiconducting electronic devices. In this work, we show a nondestructive method of characterizing the layer number of two-dimensional (2-D) MoSe2 and WSe2 including single- and few-layer materials by Raman spectroscopy. The related photoluminescence properties are also studied as a reference. Although Raman spectroscopy is a powerful tool for determining the layer number of 2-D materials such as graphene and molybdenum disulfide (MoS2), there have been difficulties in precisely characterizing the layer number for MoSe2 and WSe2 by Raman spectroscopy due to the uncertain shifts during the Raman measurement process and the lack of multiple separated Raman peaks in MoSe2 and WSe2 for referencing. We then compared the normalized Si peak with MoSe2 and WSe2 and successfully identified the layer number of MoSe2 and WSe2. Similar to graphene and MoS2, the sample layer number is found to modify their optical properties up to 4 layers.

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Niu, Yue, Sergio Gonzalez-Abad, Riccardo Frisenda, Philipp Marauhn, Matthias Drüppel, Patricia Gant, Robert Schmidt, et al. "Thickness-Dependent Differential Reflectance Spectra of Monolayer and Few-Layer MoS2, MoSe2, WS2 and WSe2." Nanomaterials 8, no. 9 (September 14, 2018): 725. http://dx.doi.org/10.3390/nano8090725.

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The research field of two dimensional (2D) materials strongly relies on optical microscopy characterization tools to identify atomically thin materials and to determine their number of layers. Moreover, optical microscopy-based techniques opened the door to study the optical properties of these nanomaterials. We presented a comprehensive study of the differential reflectance spectra of 2D semiconducting transition metal dichalcogenides (TMDCs), MoS2, MoSe2, WS2, and WSe2, with thickness ranging from one layer up to six layers. We analyzed the thickness-dependent energy of the different excitonic features, indicating the change in the band structure of the different TMDC materials with the number of layers. Our work provided a route to employ differential reflectance spectroscopy for determining the number of layers of MoS2, MoSe2, WS2, and WSe2.

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Chikukwa, Evernice, Edson Meyer, Johannes Mbese, and Nyengerai Zingwe. "Colloidal Synthesis and Characterization of Molybdenum Chalcogenide Quantum Dots Using a Two-Source Precursor Pathway for Photovoltaic Applications." Molecules 26, no. 14 (July 9, 2021): 4191. http://dx.doi.org/10.3390/molecules26144191.

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The drawbacks of utilizing nonrenewable energy have quickened innovative work on practical sustainable power sources (photovoltaics) because of their provision of a better-preserved decent environment which is free from natural contamination and commotion. Herein, the synthesis, characterization, and application of Mo chalcogenide nanoparticles (NP) as alternative sources in the absorber layer of QDSSCs is discussed. The successful synthesis of the NP was confirmed as the results from the diffractive peaks obtained from XRD which were positive and agreed in comparison with the standard. The diffractive peaks were shown in the planes (100), (002), (100), and (105) for the MoS2 nanoparticles; (002), (100), (103), and (110) for the MoSe2 nanoparticles; and (0002), (0004), (103), as well as (0006) for the MoTe2 nanoparticles. MoSe2 presented the smallest size of the nanoparticles, followed by MoTe2 and, lastly, by MoS2. These results agreed with the results obtained using SEM analysis. For the optical properties of the nanoparticles, UV–Vis and PL were used. The shift of the peaks from the red shift (600 nm) to the blue shift (270–275 nm and 287–289 nm (UV–Vis)) confirmed that the nanoparticles were quantum-confined. The application of the MoX2 NPs in QDSSCs was performed, with MoSe2 presenting the greatest PCE of 7.86%, followed by MoTe2 (6.93%) and, lastly, by MoS2, with the PCE of 6.05%.

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Hu, J. J., J. H. Sanders, and J. S. Zabinski. "Synthesis and microstructural characterization of inorganic fullerene-like MoS2 and graphite-MoS2 hybrid nanoparticles." Journal of Materials Research 21, no. 4 (April 1, 2006): 1033–40. http://dx.doi.org/10.1557/jmr.2006.0118.

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The structures of inorganic fullerene-like (IF) MoS2 nanoparticles produced by arc discharge in water are reported in this paper. To adjust the chemistry and structure of IF nanoparticles, 2H–MoS2, graphite and composite 2H–MoS2/graphite rods were used as electrodes in the arc synthesis. In comparison to using MoS2 as both anode and cathode, mixed electrodes (graphite and MoS2) significantly increased the discharge current. Various IF-MoS2 nanoparticles were successfully produced by the water-based arc method, and their microstructures were studied using a transmission electron microscope equipped with an x-ray energy dispersive spectrometer. The IF–MoS2 nanoparticles commonly had a solid core wrapped with a few MoS2 layers and exhibit some differences in size and geometry. The IF-MoS2 nanoparticles were typically 5–30 nm in diameter as observed by transmission electron microscopy. Tiny IF-MoS2 nanoparticles (<10 nm) along with fragments of lamellar MoS2 were produced from arc discharge in water using both graphite and MoS2 electrodes. Carbon nano-onions and hybrid nanoparticles consisting of carbon and MoS2 were synthesized by using mixed electrodes of graphite and 2H–MoS2. The hybrid nanoparticles were MoS2 cores covered by a graphite shell. Our results show that the water-based arc method provides a simple tool for producing a variety of nanoparticles including some familiar and some new hybrid structures.

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Politano, Grazia Giuseppina, Marco Castriota, Maria Penelope De Santo, Mario Michele Pipita, Giovanni Desiderio, Carlo Vena, and Carlo Versace. "Variable Angle Spectroscopic Ellipsometry Characterization of Spin-Coated MoS2 Films." Materials Proceedings 4, no. 1 (November 12, 2020): 86. http://dx.doi.org/10.3390/iocn2020-07978.

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In the field of Transition Metal Dichalcogenides (TMDCs), molybdenum disulfide (MoS2) has attracted an outstanding interest due to it having several applications. MoS2 has potentialities not yet fully realized in solution-based applications. However, the lack of knowledge of the optical properties of MoS2, especially in the infrared range, has significantly limited its use in many exciting photonic fields. In this work, the broadband optical properties of MoS2 films deposited by spin-coating onto Si/SiO2 substrates were studied by means of Variable Angle Spectroscopic Ellipsometry (VASE). The morphological and the structural properties of the samples were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Micro-Raman Spectroscopy. Micro-Raman spectroscopy measurements reveal the presence of 2H-MoS2 and 1T-MoS2 phases. The optical properties of the films show a mid-gap state at 0.6 eV, not reported in an ellipsometry work before, induced by defects in the MoS2 samples.

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Zhang, Huiying, Xiang Li, Wenjie Qian, Jianguo Zhu, Beibei Chen, Jin Yang, and Yu Xia. "Characterization of mechanical properties of epoxy/nanohybrid composites by nanoindentation." Nanotechnology Reviews 9, no. 1 (February 18, 2020): 28–40. http://dx.doi.org/10.1515/ntrev-2020-0003.

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AbstractThe carbon nanofibers and molybdenum disulfide (CNF-MoS2) nanohybrid material was fabricated and incorporated into epoxy resin to form the nanocomposite coating. Firstly, microstructure observation shows that each CNF was uniformly wrapped up with MoS2 nanosheets, and the nanohybrids were well dispersed in the coating. Then, nanoindentation experiments were carried out to explore the effect of the CNF-MoS2 nanohybrids on the mechanical properties of the epoxy resin coating. The results demonstrate that elastic modulus, hardness and creep deformation resistance of the CNF-MoS2 epoxy resin coating are greatly increased in comparison with both pure epoxy resin and MoS2 epoxy resin coatings. Finally, the underlying mechanism of high-performance tribological behavior of the nanocomposites is analyzed accordingly. It can be concluded that the wrapped structure with MoS2 sheets growing on the surface of CNF increases the contact area and reduces the friction coefficient of the composite coating, while the wear resistance of the nanocomposite coating is also greatly improved due to the superior high hardness of CNF.

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Venkateswarlu, Gundu, Devarapaga Madhu, and Jetti Vatsala Rani. "Electroanalytical characterization of F-doped MoS2 cathode material for rechargeable magnesium battery." Functional Materials Letters 12, no. 03 (May 16, 2019): 1950041. http://dx.doi.org/10.1142/s1793604719500413.

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Fluorine (F)-doped MoS2 was prepared by F-doping into layered MoS2 via chemical solution process with fluoroboric acid. X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were applied to conform the effect of F on the structure. The electrochemical performance was investigated by using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge studies. The F-doped MoS2 as cathode material for rechargeable Mg battery exhibited a good discharge capacity of 55[Formula: see text]mAhg[Formula: see text], with a good rate capability and good cycling stability when compared to pristine B-MoS2. The effective performance of F-doped MoS2 are attributed to the unique structure and synergetic effect between layered MoS2.

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Hu, Kun Hong, Xian Guo Hu, Xiao Jun Sun, He Feng Jing, and Song Zhan. "Synthesis and Characterization of Nanosize Molybdenum Disulfide Particles by Quick Homogeneous Precipitation Method." Key Engineering Materials 353-358 (September 2007): 2107–10. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2107.

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Molybdenum sulfide nanoparticles were prepared via quick homogeneous precipitation method (QHPM) by the reaction between Na2MoO4 and CH3CSNH2 in the presence of sulfuric acid at 80 oC. The as-synthesized molybdenum sulfide particles were studied by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The results showed that the as-synthesized molybdenum sulfide was amorphous MoS3 nanoparticles with an average size of 40 nm. The resultant amorphous MoS3 nanoparticles were then calcined under hydrogen gas flow at a selected temperature for 50 minutes. The results of XRD, TEM, and HRTEM confirmed that the MoS2 nanoparticles with about 40 nm were prepared from the amorphous MoS3 nanoparticles at 780 oC.

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Abid, Mohammad F., Mohammed A. Hamza, Shakir M. Ahmed, Salah M. Ali, and Sattar J. Hussein. "SYNTHESIS AND CHARACTERIZATION OF UNSUPPORTED CATALYST FOR GAS OIL DESULFURIZATION." Al-Qadisiyah Journal for Engineering Sciences 11, no. 3 (January 31, 2019): 357–71. http://dx.doi.org/10.30772/qjes.v11i3.566.

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Unsupported MoS2 catalysts were synthesized for the hydrodesulfurization (HDS) of real feed gas oil using different temperatures and pressures. Hydrothermal method was utilized to prepare by using molybdenum trioxide and sodium sulfide. The characterization of the catalyst was identified by XRD, SEM, and BET techniques. It was found that BET surface and pore volume were positively affected by pressure and temperature that could improve the activity of MoS2. Kinetic analysis showed that HDS reaction over MoS2 follow pseudo-first order kinetics. Experimental results revealed that the HDS activity of the unsupported MoS2 catalyst was better than supported CoMo/Al2O3 catalyst under the same operating conditions.

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11

Garadkar, K. M., A. A. Patil, P. P. Hankare, P. A. Chate, D. J. Sathe, and S. D. Delekar. "MoS2: Preparation and their characterization." Journal of Alloys and Compounds 487, no. 1-2 (November 2009): 786–89. http://dx.doi.org/10.1016/j.jallcom.2009.08.069.

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12

Virsek, Marko, Matthias Krause, Andreas Kolitsch, and Maja Remškar. "Raman characterization of MoS2 microtube." physica status solidi (b) 246, no. 11-12 (October 9, 2009): 2782–85. http://dx.doi.org/10.1002/pssb.200982281.

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13

Giubileo, Filippo, Alessandro Grillo, Maurizio Passacantando, Francesca Urban, Laura Iemmo, Giuseppe Luongo, Aniello Pelella, Melanie Loveridge, Luca Lozzi, and Antonio Di Bartolomeo. "Field Emission Characterization of MoS2 Nanoflowers." Nanomaterials 9, no. 5 (May 9, 2019): 717. http://dx.doi.org/10.3390/nano9050717.

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Nanostructured materials have wide potential applicability as field emitters due to their high aspect ratio. We hydrothermally synthesized MoS2 nanoflowers on copper foil and characterized their field emission properties, by applying a tip-anode configuration in which a tungsten tip with curvature radius down to 30–100 nm has been used as the anode to measure local properties from small areas down to 1–100 µm2. We demonstrate that MoS2 nanoflowers can be competitive with other well-established field emitters. Indeed, we show that a stable field emission current can be measured with a turn-on field as low as 12 V/μm and a field enhancement factor up to 880 at 0.6 μm cathode–anode separation distance.

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Mouloua, Driss, Ahmed Kotbi, Geetanjali Deokar, Khaled Kaja, Mimoun El Marssi, My Ali EL Khakani, and Mustapha Jouiad. "Recent Progress in the Synthesis of MoS2 Thin Films for Sensing, Photovoltaic and Plasmonic Applications: A Review." Materials 14, no. 12 (June 14, 2021): 3283. http://dx.doi.org/10.3390/ma14123283.

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In the surge of recent successes of 2D materials following the rise of graphene, molybdenum disulfide (2D-MoS2) has been attracting growing attention from both fundamental and applications viewpoints, owing to the combination of its unique nanoscale properties. For instance, the bandgap of 2D-MoS2, which changes from direct (in the bulk form) to indirect for ultrathin films (few layers), offers new prospects for various applications in optoelectronics. In this review, we present the latest scientific advances in the field of synthesis and characterization of 2D-MoS2 films while highlighting some of their applications in energy harvesting, gas sensing, and plasmonic devices. A survey of the physical and chemical processing routes of 2D-MoS2 is presented first, followed by a detailed description and listing of the most relevant characterization techniques used to study the MoS2 nanomaterial as well as theoretical simulations of its interesting optical properties. Finally, the challenges related to the synthesis of high quality and fairly controllable MoS2 thin films are discussed along with their integration into novel functional devices.

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Neupane, Guru P., Minh Dao Tran, Hyun Kim, and Jeongyong Kim. "Modulation of Optical and Electrical Characteristics by Laterally Stretching DNAs on CVD-Grown Monolayers of MoS2." Journal of Nanomaterials 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/2565703.

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Monolayer MoS2 (1L-MoS2) is an ideal platform to examine and manipulate two dimensionally confined exciton complexes, which provides a large variety of modulating the optical and electrical properties of 1L-MoS2. Extensive studies of external doping and hybridization exhibit the possibilities of engineering the optical and electrical performance of 1L-MoS2. However, biomodifications of 1L-MoS2 and the characterization and applications of such hybrid structures are rarely reported. In this paper, we present a bio-MoS2 hybrid structure fabricated by laterally stretching strands of DNAs on CVD-grown 1L-MoS2. We observed a strong modification of photoluminescence and Raman spectra with reduced PL intensity and red-shift of PL peak and Raman peaks, which were attributed to electron doping by the DNAs and the presence of tensile strain in 1L-MoS2. Moreover, we observed a significant enhancement of electric mobility in the DNA/1L-MoS2 hybrid compared to that in the pristine 1L-MoS2, which may have been caused by the induced strain in 1L-MoS2.

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Cui, Ya Ru, Jiang Shan He, Xiao Ming Li, Jun Xue Zhao, Ao Li Chen, and Jun Yang. "Preparation and Characterization of MoS₂Microsphere by Hydrothermal Method." Advanced Materials Research 631-632 (January 2013): 306–9. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.306.

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In this work, MoS2 microsphere was synthesized by hydrothermal reaction, in which thiourea (CS(NH2)2) was used as S-source and reducing agent, ammonium heptamolybdate ((NH4)6Mo7O24.4H2O) was used as Mo-source. The influence of temperature, as well as different dispersing agents, on the reaction product’s morphology, structure and phase composition was discussed. X-ray diffraction results show that all the as-synthesized products are the hexagonal 2H-MoS2 without impurity. SEM images of the as-prepared MoS2 samples without adding any dispersing agent present spherical morphology with sheet-like structures shaped on the surface. A possible formation mechanism of the MoS2 microsphere is that of self-assembly growth process; In addition, for the samples adding surfactant CTAB, SDBS or PVP in the reactants, the MoS2 is confined to layered structure. Compared with SDBS and PVP, CTAB has the best dispersion effect which ensure the as-synthesized microsphere with about 300nm average diameter, and the influence mechanism of which can be deduced as electrostatic interaction and stereo-hindrance effect.

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Zheng, Jiahong, Kangkang Cheng, Runmei Zhang, Yamei Yang, Yuntao Wu, and Pengfei Yu. "Si Quantum Dots Assist Synthesized Microflower-Like Si/MoS2 Composites for Supercapacitors." Crystals 10, no. 9 (September 22, 2020): 846. http://dx.doi.org/10.3390/cryst10090846.

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The microflower-like Si/MoS2 composites were fabricated using Si quantum dots (QDs) to assist a facile hydrothermal method. The electrochemical performance of Si/MoS2 composite in symmetric and asymmetric systems was studied. Electrochemical characterization revealed that the Si/MoS2 composite electrode in a three-electrode system has a high specific capacitance of 574.4 F·g−1 at 5 A·g−1. Furthermore, the Si/MoS2 composite electrode in a two-electrode system had the maximum energy density of 27.2 Wh·kg−1 when a power density of 749.1 W·kg−1 was achieved. Therefore, this investigation proves the Si/MoS2 composite microflower-like structure should be a promising candidate electrode material for supercapacitors.

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Gu, Le, Guo Jian Cao, Li Qin Wang, and Xin Xin Ma. "Synthesis and Characterization of a Self-Lubricating Film on Bearing Balls." Advanced Materials Research 154-155 (October 2010): 367–70. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.367.

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In this work, the feasibility of using planetary ball milling for coating bearing balls with a self-lubricating film was investigated. Bearing balls with appropriate amount of MoS2 powder were put into vacuumed stainless steel vials and ball milled. With proceeding of ball milling, thickness of the self-lubricating film increased at first and then decreased. X-ray diffraction (XRD) and X-ray photoelectron spectrum (XPS) results revealed that the surface of the self-lubricating film was MoS2 and the inner region was a mixture of iron molybdenum alloys (Fe3Mo, FexMoy), MoS2 and FeS. Friction coefficient between the self-lubricating film and bear steel was 0.06~0.1.

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Viswan, Gauthami, S. Reshmi, P. S. Sachidanand, Manu Mohan, and K. Bhattacharjee. "Electrical Characterization of Tailored MoS2 Nanostructures." IOP Conference Series: Materials Science and Engineering 577 (December 7, 2019): 012163. http://dx.doi.org/10.1088/1757-899x/577/1/012163.

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20

Castillo, Karina, Felicia Manciu, J. G. Parsons, and Russell R. Chianelli. "Synthesis and characterization of 1,2,3,4 tetrahydroquinoline intercalated into MoS2 in search of cleaner fuels." Journal of Materials Research 22, no. 10 (October 2007): 2747–57. http://dx.doi.org/10.1557/jmr.2007.0343.

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Two different morphologies of MoS2 (short and long sheets) were utilized to elucidate the intercalation mechanism of 1,2,3,4 tetrahydroquinoline (THQ). MoS2 (short sheets) and molybdenite (MB) (long sheets) were exfoliated and restacked in the presence of THQ. The x-ray diffraction patterns of both samples show a new reflection in the 001 plane, which implies a lowering of symmetry and corresponds to an expansion of the layers by approximately 12.3 Å. In the MoS2-THQ sample, 80% of the MoS2 was intercalated and 20% remained stacked. In the MB-THQ sample, 30% of MB was intercalated while 70% remained stacked. X-ray absorption structure (XAS) studies showed changes in atomic geometry and coordination. The x-ray absorption near-edge spectra showed shifts in the geometry of the intercalated MoS2 and MB sample compared to the unintercalated samples. Extended x-ray absorption fine structure studies showed lower coordination numbers compared to the untreated samples. Infrared spectroscopy characterization of these same samples suggests intercalation and partial dehydrogenation of the THQ.

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Murugan, A. Vadivel, Mathieu Quintin, Marie-Helene Delville, Guy Campet, Annamraju Kasi Viswanath, Chinnakonda S. Gopinath, and K. Vijayamohanan. "Synthesis and characterization of organic–inorganic poly(3,4-ethylenedioxythiophene)/MoS2 nanocomposite via in situ oxidative polymerization." Journal of Materials Research 21, no. 1 (January 1, 2006): 112–18. http://dx.doi.org/10.1557/jmr.2006.0015.

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Here we demonstrate the synthesis of a new type of layered poly(3,4-ethylenedioxy- thiophene) (PEDOT)/MoS2 nanocomposite via flocculation of delaminated MoS2 with subsequent in situ oxidative polymerization of 3,4-ethylenedioxythiophene. The resulting nanocomposite was characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, thermal analysis, transmission electron microscopy, and four-probe electrical conductivity measurements with respect to temperature. X-ray diffraction results indicated that the exfoliated MoS2 and PEDOT are restacked to produce a novel nanoscale composite material containing alternate nanoribbons of PEDOT in between MoS2 with a basal distance of ∼1.38 nm. The nanocomposite, which could be used as a cathode material for small power rechargeable lithium batteries, has also been demonstrated by the electrochemical insertion of lithium into the PEDOT/MoS2 nanocomposite, where a significant enhancement in the discharge capacity is observed, compared to that of respective pristine molybdenum disulfide.

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Liu, Zhe, Liwei Wang, Ruoping Li, and Mingju Huang. "Synthesis of Au@MoS2-CdS Ternary Composite Structure with Enhanced Photocatalytic Activity." Nano 14, no. 09 (September 2019): 1950114. http://dx.doi.org/10.1142/s1793292019501145.

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Au@MoS2-CdS, as ternary composite structure, was successfully synthesized by a facile process combining hydrothermal and seed-growth methods. The introduction of Au nanoparticles (NPs) into MoS2 spheres, forming a core–shell structure, demonstrates strong plasmonic absorption enhancement. The incorporation of CdS NPs into the Au@MoS2 core–shell structure further extends the absorption range of visible light and enhances exciton dissociation. The resultant composite structure exhibits the highest photocatalytic activity in photocatalytic degradation of rhodamine B (RhB) solution, compared with Au NPs, MoS2 spheres, Au@MoS2 core–shell and MoS2-CdS heterostructures. The above phenomena are supported by a series of characterization results such as SEM, TEM, XRD, EDS and UV-Vis, etc. Based on structural and morphological analyses, we propose the synthesis method of ternary composite structure photocatalysts, which is helpful for the synthesis of future multicomponent photocatalytic materials.

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Iemmo, Laura, Francesca Urban, Filippo Giubileo, Maurizio Passacantando, and Antonio Di Bartolomeo. "Nanotip Contacts for Electric Transport and Field Emission Characterization of Ultrathin MoS2 Flakes." Nanomaterials 10, no. 1 (January 4, 2020): 106. http://dx.doi.org/10.3390/nano10010106.

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We report a facile approach based on piezoelectric-driven nanotips inside a scanning electron microscope to contact and electrically characterize ultrathin MoS2 (molybdenum disulfide) flakes on a SiO2/Si (silicon dioxide/silicon) substrate. We apply such a method to analyze the electric transport and field emission properties of chemical vapor deposition-synthesized monolayer MoS2, used as the channel of back-gate field effect transistors. We study the effects of the gate-voltage range and sweeping time on the channel current and on its hysteretic behavior. We observe that the conduction of the MoS2 channel is affected by trap states. Moreover, we report a gate-controlled field emission current from the edge part of the MoS2 flake, evidencing a field enhancement factor of approximately 200 and a turn-on field of approximately 40 V / μ m at a cathode–anode separation distance of 900 nm .

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Walck, S. D., M. S. Donley, J. S. Zabinski, and V. J. Dyhouse. "Characterization of pulsed laser deposited PbO/MoS2 by transmission electron microscopy." Journal of Materials Research 9, no. 1 (January 1994): 236–45. http://dx.doi.org/10.1557/jmr.1994.0236.

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Films of PbO/MoS2, grown by pulsed laser deposition, exhibit a significant improvement in tribological performance compared to MoS2 films grown by the same process. The microstructure and crystallography of PbO/MoS2 composite films were investigated using transmission electron microscopy (TEM) to identify the features responsible for this tribological improvement. Self-supporting samples were prepared from pulsed laser deposited, PbO/MoS2 thin films grown on single crystal sodium chloride substrates. Films deposited at room temperature exhibited a two-phase microstructure with one of the phases being amorphous. X-ray microanalysis results showed that the crystalline phase had significantly higher concentration ratios of Mo/Pb, Mo/S, and Pb/S than did the amorphous phase. Films grown at 300 °C were polycrystalline, with a grain size of about 20 nm, and had a NaCl type structure which was isomorphous to PbS. The grains had rectangular shape, and exhibited preferred orientation with the sodium chloride substrate. The concentration of S for these films was approximately 80% of the S concentration for films grown at room temperature. Both the high temperature and room temperature films had S concentrations which were higher than expected from the MoS2 in the target; this was attributed to gettering of the S in the vacuum chamber by Pb. The electron diffraction results, together with previously published results, suggest that the crystal structure of the phases in these films is not responsible for the improvement in tribological properties. However, the microstructural components formed during film growth do determine the wear-induced chemical reaction pathways.

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Mahdavi, Mitra, Salimeh Kimiagar, and Fahimeh Abrinaei. "Preparation of Few-Layered Wide Bandgap MoS2 with Nanometer Lateral Dimensions by Applying Laser Irradiation." Crystals 10, no. 3 (March 2, 2020): 164. http://dx.doi.org/10.3390/cryst10030164.

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In this study, we report a new method for the quick, green, and one-step preparation of few-layered molybdenum disulfide (MoS2) nanosheets with wide bandgap. MoS2 nanosheets with small lateral dimension and uniform size distribution were synthesized for various applications. MoS2 powder was synthesized using the hydrothermal method; then, thinned by applying laser irradiation with different energies from 40 to 80 mJ. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis absorption spectra, and photoluminescence (PL) spectra were applied for the characterization of the MoS2 nanosheets in terms of morphology, crystal structures, and optical properties. The widest calculated bandgap 4.7 eV was for the sample under 80 mJ laser energy. The results confirmed the successful preparation of highly pure, uniform, and few-layered MoS2 nanosheets. Furthermore, it was possible to enhance the production rate of MoS2 nanosheets (including nanosheets and nanoparticles) through laser irradiation. Thus, the present paper introduces a simple and green alternative approach for preparing few-layered MoS2 nanosheets of transition metal dichalcogenides or other layered materials.

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Zhang, Xiao-Mei, Sian-Hong Tseng, and Ming-Yen Lu. "Large-Area Ultraviolet Photodetectors Based on p-Type Multilayer MoS2 Enabled by Plasma Doping." Applied Sciences 9, no. 6 (March 15, 2019): 1110. http://dx.doi.org/10.3390/app9061110.

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Two-dimensional (2D) MoS2 has recently become of interest for applications in broad range photodetection due to their tunable bandgap. In order to develop 2D MoS2 photodetectors with ultrafast response and high responsivity, up-scalable techniques for realizing controlled p-type doping in MoS2 is necessary. In this paper, we demonstrate a p-type multilayer MoS2 photodetector with selective-area doping using CHF3 plasma treatment. Microscopic and spectroscopic characterization techniques, including atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), are used to investigate the morphological and electrical modification of the p-type doped MoS2 surface after CHF3 plasma treatment. Back-gated p-type MoS2 field-effect transistors (FETs) are fabricated with an on/off current ratio in the order of 103 and a field-effect mobility of 65.2 cm2V−1s−1. They exhibit gate-modulated ultraviolet photodetection with a rapid response time of 37 ms. This study provides a promising approach for the development of mild plasma-doped MoS2 as a 2D material in post-silicon electronic and optoelectronic device applications.

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Favaro, Marco, Mattia Cattelan, Stephen W. T. Price, Andrea E. Russell, Laura Calvillo, Stefano Agnoli, and Gaetano Granozzi. "In Situ Study of Graphene Oxide Quantum Dot-MoSx Nanohybrids as Hydrogen Evolution Catalysts." Surfaces 3, no. 2 (June 16, 2020): 225–36. http://dx.doi.org/10.3390/surfaces3020017.

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Graphene quantum dots (GOQDs)-MoSx nanohybrids with different MoSx stoichiometries (x = 2 and 3) were prepared in order to investigate their chemical stability under hydrogen evolution reaction (HER) conditions. Combined photoemission/electrochemical (XPS/EC) measurements and operando X-ray absorption spectroscopy (XAS) were employed to determine the chemical changes induced on the MoSx-based materials as a function of the applied potential. This in situ characterization indicates that both MoS2 and MoS3 materials are stable under operating conditions, although sulfur terminal sites in the MoS3 nanoparticles are converted from S-dimer (S22−) to S-monomer (S2−), which constitute the first sites where the hydrogen atoms are adsorbed for their subsequent evolution. In order to complete the characterization of the GOQDs-MoSx nanohybrids, the composition and particle size were determined by X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy; whereas the HER activity was studied by conventional electrochemical techniques.

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Karki, Hem Prakash, Hyojae Kim, Jinmu Jung, and Jonghyun Oh. "Synthesis of Molybdenum Sulfide/Tellurium Hetero-Composite by a Simple One-Pot Hydrothermal Technique for High-Performance Supercapacitor Electrode Material." Nanomaterials 11, no. 9 (September 9, 2021): 2346. http://dx.doi.org/10.3390/nano11092346.

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It is necessary to investigate effective energy storage devices that can fulfill the requirements of short-term and long-term durable energy outputs. Here, we report a simple one-pot hydrothermal technique through which to fabricate the MoS2/Te nanocomposite to be used as an effective electrode material for high-performance supercapacitors. Comprehensive characterization of the as-fabricated nanomaterial was performed using FESEM, HRTEM, XRD, FTIR, XPS, etc., as well as electrochemical characterizations. The electrochemical characterization of the as-fabricated nanocomposite electrode material showed a high specific capacitance of 402.53 F g−1 from a galvanostatic charge-discharge (GCD) profile conducted at 1 A g−1 current density. The electrode material also showed significant rate performance with high cyclic stability reaching up to 92.30% under 4000 cycles of galvanostatic charge-discharge profile at a current density of 10 A g−1. The highly encouraging results obtained using this simple synthetic approach demonstrate that the hetero-structured nanocomposite of MoS2/Te electrode material could serve as a promising composite to use in effective supercapacitors or energy storage devices.

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Han, Tao, Hongxia Liu, Shupeng Chen, Yanning Chen, Shulong Wang, and Zhandong Li. "Fabrication and Characterization of MoS2/h-BN and WS2/h-BN Heterostructures." Micromachines 11, no. 12 (December 16, 2020): 1114. http://dx.doi.org/10.3390/mi11121114.

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The general preparation method of large-area, continuous, uniform, and controllable vdW heterostructure materials is provided in this paper. To obtain the preparation of MoS2/h-BN and WS2/h-BN heterostructures, MoS2 and WS2 material are directly grown on the insulating h-BN substrate by atmospheric pressure chemical vapor deposition (APCVD) method, which does not require any intermediate transfer steps. The test characterization of MoS2/h-BN and WS2/h-BN vdW heterostructure materials can be accomplished by optical microscope, AFM, Raman and PL spectroscopy. The Raman peak signal of h-BN material is stronger when the h-BN film is thicker. Compared to the spectrum of MoS2 or WS2 material on SiO2/Si substrate, the Raman and PL spectrum peak positions of MoS2/h-BN heterostructure are blue-shifted, which is due to the presence of local strain, charged impurities and the vdW heterostructure interaction. Additionally, the PL spectrum of WS2 material shows the strong emission peak at 1.96 eV, while the full width half maximum (FWHM) is only 56 meV. The sharp emission peak indicates that WS2/h-BN heterostructure material has the high crystallinity and clean interface. In addition, the peak position and shape of IPM mode characteristic peak are not obvious, which can be explained by the Van der Waals interaction of WS2/h-BN heterostructure. From the above experimental results, the preparation method of heterostructure material is efficient and scalable, which can provide the important support for the subsequent application of TMDs/h-BN heterostructure in nanoelectronics and optoelectronics.

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An, Vladimir, Herman Potgieter, Natalia Usoltseva, Damir Valiev, Sergei Stepanov, Alexey Pustovalov, Arsenii Baryshnikov, Maksim Titov, and Alesya Dolinina. "MoS2@ZnO Nanoheterostructures Prepared by Electrospark Erosion for Photocatalytic Applications." Nanomaterials 11, no. 1 (January 9, 2021): 157. http://dx.doi.org/10.3390/nano11010157.

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MoS2@ZnO nanoheterostructures were synthesized by electrospark erosion of zinc granules in a hydrogen peroxide solution and simultaneous addition of MoS2 nanostructured powder into the reaction zone. The morphology, size of the crystallites, as well as elemental and phase composition of the prepared structures, were examined using transmission electron microscopy and X-ray diffraction analysis. It was found that the synthesized products represent heterostructures containing MoS2 nanoparticles formed on ZnO nanoparticles. Raman spectroscopy and photoluminescence analysis were also used for characterization of the prepared heterostructures. The obtained MoS2@ZnO nanostructures revealed an intense broad emission band ranging from 425 to 625 nm for samples with different fractions of MoS2. Photocatalytic measurements showed that the maximal hydrogen evolution rate of the prepared nanoheterostructures was about 906.6 μmolg−1h−1.The potential of their application in photocatalytic water splitting was also estimated.

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An, Vladimir, Herman Potgieter, Natalia Usoltseva, Damir Valiev, Sergei Stepanov, Alexey Pustovalov, Arsenii Baryshnikov, Maksim Titov, and Alesya Dolinina. "MoS2@ZnO Nanoheterostructures Prepared by Electrospark Erosion for Photocatalytic Applications." Nanomaterials 11, no. 1 (January 9, 2021): 157. http://dx.doi.org/10.3390/nano11010157.

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MoS2@ZnO nanoheterostructures were synthesized by electrospark erosion of zinc granules in a hydrogen peroxide solution and simultaneous addition of MoS2 nanostructured powder into the reaction zone. The morphology, size of the crystallites, as well as elemental and phase composition of the prepared structures, were examined using transmission electron microscopy and X-ray diffraction analysis. It was found that the synthesized products represent heterostructures containing MoS2 nanoparticles formed on ZnO nanoparticles. Raman spectroscopy and photoluminescence analysis were also used for characterization of the prepared heterostructures. The obtained MoS2@ZnO nanostructures revealed an intense broad emission band ranging from 425 to 625 nm for samples with different fractions of MoS2. Photocatalytic measurements showed that the maximal hydrogen evolution rate of the prepared nanoheterostructures was about 906.6 μmol·g−1·h−1. The potential of their application in photocatalytic water splitting was also estimated.

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Ramohlola, Kabelo E., Emmanuel I. Iwuoha, Mpitloane J. Hato, and Kwena D. Modibane. "Instrumental Techniques for Characterization of Molybdenum Disulphide Nanostructures." Journal of Analytical Methods in Chemistry 2020 (December 16, 2020): 1–29. http://dx.doi.org/10.1155/2020/8896698.

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The excellent chemical and physical properties of materials (nanomaterials) with dimensions of less than 100 nm (nanometers) resulted in researchers and industrialists to have great interest in their discovery and applications in various systems/applications. As their sizes are reduced to nanoscale, these nanomaterials tend to possess exceptional properties differing from those of their bulk counterparts; hence, they have found applications in electronics and medicines. In order to apply them in those applications, there is a need to synthesise these nanomaterials and study their structural, optical, and electrochemical properties. Among several nanomaterials, molybdenum disulphide (MoS2) has received a great interest in energy applications due to its exceptional properties such as stability, conductivity, and catalytic activities. Hence, the great challenge lies in finding the state-of-the-art characterization techniques to reveal the different properties of MoS2 nanostructures with great accuracy. In this regard, there is a need to study and employ several techniques to accurately study the surface chemistry and physics of the MoS2 nanostructures. Hence, this review will comprehensively discuss a detailed literature survey on analytical techniques that can be used to study the chemical, physical, and surface properties of MoS2 nanostructures, namely, ultraviolet-visible spectroscopy (UV-vis), photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, time-of-flight secondary ion mass spectroscopy (TOF-SIMS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopies (SEM and TEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS/X), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and electroanalytical methods which include linear sweep (LSV) and cyclic (CV) voltammetry and electrochemical impedance spectroscopy (EIS).

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Du, Hao, Chao Sun, Jun Gong, and Soo Wohn Lee. "Deposition and Characterization of D-Gun Sprayed WC-Co Coating with Self-Lubricating Property." Materials Science Forum 544-545 (May 2007): 215–18. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.215.

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A WC-Co coating with self-lubricating property was deposited by detonation gun (D-gun) process, using a WC-Co powder doped with a MoS2-Ni powder, under a proper spray condition. It is proved that the MoS2 composition was kept in the resulting coating by SEM, XRD and EPMA. Evaluation on sliding wear property indicates that the MoS2 composition plays an important role in lowering both coefficient of friction and wear rate for the resulting coating, which is confirmed by observations on wear track. It suggests that the deposition of WC-Co coating with self-lubricating property by D-gun spray is feasible by controlling lubricant powder and spray conditions, which can exhibit higher sliding wear resistance.

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Prabhu, Mahesh K., and Irene M. N. Groot. "Low-Temperature Synthesis Strategy for MoS2 Slabs Supported on TiO2(110)." Surfaces 3, no. 4 (November 5, 2020): 605–21. http://dx.doi.org/10.3390/surfaces3040041.

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MoS2 supported on oxides like TiO2 has a broad range of applications. The atomic structure of this system is therefore very useful to study. Previous research work in this area has made use of high-temperature synthesis methods, while the preparation of an MoS2/TiO2 in very important applications, such as catalysis, makes use of a low-temperature synthesis method. In this work, we investigate a low-temperature synthesis strategy for MoS2 slabs supported on rutile TiO2(110). Using scanning tunneling microscopy and X-ray photoelectron spectroscopy, we demonstrate that not only flat MoS2 slabs with irregular shapes but also MoSx stripes with a large number of coordinatively unsaturated Mo atoms are formed. In particular, it becomes evident that, for atomic structural characterization of MoS2/TiO2 and similar oxide-supported systems grown by low-temperature synthesis methods, the surface structure of the support becomes highly relevant.

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Kaindl, Reinhard, Bernhard C. Bayer, Roland Resel, Thomas Müller, Viera Skakalova, Gerlinde Habler, Rainer Abart, et al. "Growth, structure and stability of sputter-deposited MoS2 thin films." Beilstein Journal of Nanotechnology 8 (May 22, 2017): 1115–26. http://dx.doi.org/10.3762/bjnano.8.113.

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Molybdenum disulphide (MoS2) thin films have received increasing interest as device-active layers in low-dimensional electronics and also as novel catalysts in electrochemical processes such as the hydrogen evolution reaction (HER) in electrochemical water splitting. For both types of applications, industrially scalable fabrication methods with good control over the MoS2 film properties are crucial. Here, we investigate scalable physical vapour deposition (PVD) of MoS2 films by magnetron sputtering. MoS2 films with thicknesses from ≈10 to ≈1000 nm were deposited on SiO2/Si and reticulated vitreous carbon (RVC) substrates. Samples deposited at room temperature (RT) and at 400 °C were compared. The deposited MoS2 was characterized by macro- and microscopic X-ray, electron beam and light scattering, scanning and spectroscopic methods as well as electrical device characterization. We find that room-temperature-deposited MoS2 films are amorphous, of smooth surface morphology and easily degraded upon moderate laser-induced annealing in ambient conditions. In contrast, films deposited at 400 °C are nano-crystalline, show a nano-grained surface morphology and are comparatively stable against laser-induced degradation. Interestingly, results from electrical transport measurements indicate an unexpected metallic-like conduction character of the studied PVD MoS2 films, independent of deposition temperature. Possible reasons for these unusual electrical properties of our PVD MoS2 thin films are discussed. A potential application for such conductive nanostructured MoS2 films could be as catalytically active electrodes in (photo-)electrocatalysis and initial electrochemical measurements suggest directions for future work on our PVD MoS2 films.

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Lin, Hongtao, Xiaoya Chen, Hongling Li, Min Yang, and Yanxing Qi. "Hydrothermal synthesis and characterization of MoS2 nanorods." Materials Letters 64, no. 15 (August 2010): 1748–50. http://dx.doi.org/10.1016/j.matlet.2010.04.032.

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Hasuike, N., S. Yamauchi, K. Seki, S. Kamoi, K. Nishio, and K. Kisoda. "Optical characterization of MoS2 sputtered thin films." Journal of Physics: Conference Series 1220 (May 2019): 012057. http://dx.doi.org/10.1088/1742-6596/1220/1/012057.

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Sun, Yanli, Shiming Wang, and Qiongsheng Wang. "Flowerlike MoS2 nanoparticles: solvothermal synthesis and characterization." Frontiers of Chemistry in China 4, no. 2 (April 18, 2009): 173–76. http://dx.doi.org/10.1007/s11458-009-0025-8.

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Lyle, Erin S., Cody McAllister, Douglas C. Dahn, and Rabin Bissessur. "Exfoliated MoS2–Polyaniline Nanocomposites: Synthesis and Characterization." Journal of Inorganic and Organometallic Polymers and Materials 30, no. 1 (September 18, 2019): 206–13. http://dx.doi.org/10.1007/s10904-019-01327-5.

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Pascual, Elena, José Manuel Iglesias, María J. Martín, and Raúl Rengel. "Electronic transport and noise characterization in MoS2." Semiconductor Science and Technology 35, no. 5 (April 3, 2020): 055021. http://dx.doi.org/10.1088/1361-6641/ab7777.

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Salazar, Anthony, Diana Sanchez, Christian Kisielowski, Jungiao Wu, Oscar Dubon, and Hector Calderon. "Characterization of MoS2 Nanorods by Electron Microscopy." Microscopy and Microanalysis 27, S1 (July 30, 2021): 2338–40. http://dx.doi.org/10.1017/s1431927621008412.

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Bhaumik, Shubrajit, and Viorel Paleu. "Wear and Rolling Contact Fatigue Analysis of AISI 52100 Bearing Steel in Presence of Additivated Lubricants." Metals 11, no. 6 (June 2, 2021): 907. http://dx.doi.org/10.3390/met11060907.

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Tribological properties of lithium potassium titanate (PT), molybdenum disulphide, and tungsten disulphide-dispersed mineral oil (MO) were investigated. The sample containing 2 wt.% WS2 exhibited the lowest coefficient of friction. However, the wear scar diameters of the additivated samples were very narrow. Extreme pressure properties of mineral oil were enhanced with the addition of additives. The rolling contact fatigue results exhibited better fatigue life of the balls in MoS2 and PT-dispersed MO. Surface characterization of the balls indicated more pitting on the balls of the MO and WS2-dispersed MO as compared to MoS2 and PT, indicating a stable film in the case of MoS2 and PT, which was confirmed by the presence of additives on ball surfaces by Raman spectrograph. The results of extended rolling contact fatigue tests proved that PT-added mineral oil provided the highest life cycles of the tested balls, followed by MoS2 and WS2-added mineral oil; thus, indicating PT as a plausible alternative to MoS2 and WS2.

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Fadil, Dalal, Ridwan H. Fayaz, and Anupama B. Kaul. "Electronic and Optical Properties Characterization of MoS2 Two-Dimensional Exfoliated nanomaterials." MRS Advances 1, no. 47 (2016): 3223–28. http://dx.doi.org/10.1557/adv.2016.523.

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ABSTRACTFor optoelectronic application, two-dimensional materials such as molybdenum disulfide (MoS2) are very promising candidate with their interesting electronic and optical properties. The layered structure of these materials makes them amenable to mechanical exfoliation to form scalable 2D atomic crystals. For width range of applications, liquid phase exfoliation using sonication and centrifugation in appropriate solvent is needed. This simple and scalable technique gives high quality of exfoliation of 2D materials without chemical reactions. In this paper, we report an example of the optical and electronic characterizations on MoS2 synthesized by liquid exfoliation in specific solvent.

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Han, Tao, Hongxia Liu, Shulong Wang, Shupeng Chen, Wei Li, and Xiaoli Yang. "Probing the Growth Improvement of Large-Size High Quality Monolayer MoS2 by APCVD." Nanomaterials 9, no. 3 (March 14, 2019): 433. http://dx.doi.org/10.3390/nano9030433.

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Two-dimensional transition metal dichalcogenides (TMDs) have attracted attention from researchers in recent years. Monolayer molybdenum disulfide (MoS2) is the direct band gap two-dimensional crystal with excellent physical and electrical properties. Monolayer MoS2 can effectively compensate for the lack of band gap of graphene in the field of nano-electronic devices, which is widely used in catalysis, transistors, optoelectronic devices, and integrated circuits. Therefore, it is critical to obtain high-quality, large size monolayer MoS2. The large-area uniform high-quality monolayer MoS2 is successfully grown on an SiO2/Si substrate with oxygen plasma treatment and graphene quantum dot solution by atmospheric pressure chemical vapor deposition (APCVD) in this paper. In addition, the effects of substrate processing conditions, such as oxygen plasma treatment time, power, and dosage of graphene quantum dot solution on growth quality and the area of the monolayer of MoS2, are studied systematically, which would contribute to the preparation of large-area high-quality monolayer MoS2. Analysis and characterization of monolayer MoS2 are carried out by Optical Microscopy, AFM, XPS, Raman, and Photoluminescence Spectroscopy. The results show that monolayer MoS2 is a large-area, uniform, and triangular with a side length of 200 μm, and it is very effective to treat the SiO2/Si substrate by oxygen plasma and graphene quantum dot solution, which would help the fabrication of optoelectronic devices.

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Yang, Xianguang, and Baojun Li. "Monolayer MoS2 for nanoscale photonics." Nanophotonics 9, no. 7 (February 3, 2020): 1557–77. http://dx.doi.org/10.1515/nanoph-2019-0533.

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AbstractTransition metal dichalcogenides are two-dimensional semiconductors with strong in-plane covalent and weak out-of-plane interactions, resulting in exfoliation into monolayers with atomically thin thickness. This creates a new era for the exploration of two-dimensional physics and device applications. Among them, MoS2 is stable in air and easily available from molybdenite, showing tunable band-gaps in the visible and near-infrared waveband and strong light-matter interactions due to the planar exciton confinement effect. In the single-layer limit, monolayer MoS2 exhibits direct band-gaps and bound excitons, which are fundamentally intriguing for achieving the nanophotonic and optoelectronic applications. In this review, we start from the characterization of monolayer MoS2 in our group and understand the exciton modes, then explore thermal excitons and band renormalization in monolayer MoS2. For nanophotonic applications, the recent progress of nanoscale laser source, exciton-plasmon coupling, photoluminescence manipulation, and the MoS2 integration with nanowires or metasurfaces are overviewed. Because of the benefits brought by the unique electronic and mechanical properties, we also introduce the state of the art of the optoelectronic applications, including photoelectric memory, excitonic transistor, flexible photodetector, and solar cell. The critical applications focused on in this review indicate that MoS2 is a promising material for nanophotonics and optoelectronics.

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Zribi, Rayhane, Antonino Foti, Maria Grazia Donato, Pietro Giuseppe Gucciardi, and Giovanni Neri. "Fabrication of a Novel Electrochemical Sensor Based on Carbon Cloth Matrix Functionalized with MoO3 and 2D-MoS2 Layers for Riboflavin Determination." Sensors 21, no. 4 (February 16, 2021): 1371. http://dx.doi.org/10.3390/s21041371.

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The preparation and characterization of a hybrid composite, based on carbon cloth (CC) matrix functionalized with two-dimensional (2D) MoS2 flakes and MoO3, and its use for developing an electrochemical sensor for the determination of riboflavin (RF) is here reported. The 2D-MoS2-MoO3CC composite was prepared by depositing 2D-MoS2 nanosheets, obtained by liquid phase exfoliation (LPE), on the surface of a carbon cloth fiber network, previously functionalized with a layer of molybdenum oxide (α-MoO3) by radio-frequency magnetron reactive sputtering technique. The 2D-MoS2-MoO3CC composite was characterized by scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX), and Raman spectroscopy. An electrochemical sensor has been then fabricated by fixing a slice of the 2D-MoS2-MoO3CC composite on the working electrode of a screen-printed carbon electrode (SPCE). The 2D-MoS2-MoO3-CC/SPCE sensor display good electrochemical characteristics which have been exploited, for the first time, in the electroanalytical determination of riboflavin (RF). The sensitivity to RF, equal to 0.67 µA mM−1 in the linear range from 2 to 40 µM, and a limit of detection (LOD) of 1.5 µM at S/N = 3, demonstrate the promising characteristics of the proposed 2D-MoS2-MoO3-CC/SPCE electrochemical sensor for the determination of riboflavin.

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Khan, Ramsha, Adeel Riaz, Sofia Javed, Rahim Jan, Muhammad Aftab Akram, and Mohammad Mujahid. "Synthesis and Characterization of MoS₂/TiO₂ Nanocomposites for Enhanced Photocatalytic Degradation of Methylene Blue under Sunlight Irradiation." Key Engineering Materials 778 (September 2018): 137–43. http://dx.doi.org/10.4028/www.scientific.net/kem.778.137.

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2D nanosheets/ nanoparticles based MoS2/TiO2 nanocomposites were prepared in different weight compositions which were further employed to investigate photocatalytic degradation of methylene blue. Anatase TiO2 powder was prepared via sol-gel reflux method using titanium tetraisopropoxide as Ti precursor. MoS2/TiO2 nanocomposites were prepared by in situ addition of exfoliated MoS2 (2D-nanosheets) in different weight ratios of 0.1%, 0.5%, 1%, 2% and 5% in TiO2 sol. Surface morphology, phase analysis, optical properties were studied using SEM, XRD, UV-Vis spectroscopy respectively. SEM results showed that TiO2 nanoparticles were completely adsorbed over the surface of MoS2 sheets as reflux synthesis was employed. Efficient charge carrier separation was achieved which reduced recombination, and hence, enhanced photo-degradation of methylene blue was observed. The hetero-structures showed less operation time in sunlight for photodegradation of methylene blue and a highest rate constant was observed by 2 wt.% loading of MoS2 on TiO2. These composites can also be used commercially as they show promising results.

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Sitara, Effat, Muhammad Fahad Ehsan, Habib Nasir, Sadia Iram, and Syeda Aqsa Batool Bukhari. "Synthesis, Characterization and Photocatalytic Activity of MoS2/ZnSe Heterostructures for the Degradation of Levofloxacin." Catalysts 10, no. 12 (November 26, 2020): 1380. http://dx.doi.org/10.3390/catal10121380.

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Antibiotics have been extensively used over the last few decades. Due to their extensive usage and persistence in the environment, they are considered as emergent pollutants. It is, therefore, important to synthesize new materials for efficient antibiotic degradation. Herein, we report the MoS2/ZnSe heterostructures prepared by a simple ultrasonication method. Heterostructures were prepared with different ratios of MoS2 and ZnSe, i.e., 1:3, 1:1 and 3:1. Characterization of the heterostructures was done by UV-vis diffused reflectance spectroscopy (UV-vis-DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and photoluminescence (PL) techniques to understand the morphology and surface chemistry. The results show that an efficient interface was formed to harness the visible light and degrade levofloxacin, which was monitored by gradual decreases in the UV-vis absorbance signal of levofloxacin. Among the prepared heterostructures and their pure counter parts, MoS2/ZnSe 3:1 (3:1 MZ) showed a better degradation activity of 73.2% as compared to pure MoS2 (29%) and ZnSe (17.1%) in the presence of visible light in a time span of two hours. The reusability studies showed that the catalytic performance of 3:1 MZ did not decrease significantly after three cycles. Moreover, the morphology and the crystal structure also remained unchanged.

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Pang, Xing, Qi Zhang, Yiwei Shao, Mingjie Liu, Dongliang Zhang, and Yulong Zhao. "A Flexible Pressure Sensor Based on Magnetron Sputtered MoS2." Sensors 21, no. 4 (February 5, 2021): 1130. http://dx.doi.org/10.3390/s21041130.

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Although two-dimensional (2D) layered molybdenum disulfide (MoS2) has widespread electrical applications in catalysis, energy storage, and photodetection, there are few reports available regarding sputtered MoS2 for piezoresistive sensors. In this research, we found that the resistance of magnetron sputtered MoS2 on a flexible substrate changed significantly and regularly when pressure was applied. Scanning electron microscope (SEM) and atomic force microscope (AFM) images revealed an MoS2 micro-grain-like structure comprising nano-scale particles with grooves between the particles. Chemical characterization data confirmed the successful growth of amorphous MoS2 on a polydimethylsiloxane (PDMS) substrate. A micro-thickness film flexible sensor was designed and fabricated. In particular, the sensor with a 1.5 μm thick polydimethylsiloxane (PDMS) substrate exhibited the best resistance performance, displaying a maximum ΔR/R of 70.39 with a piezoresistive coefficient as high as 866.89 MPa−1 while the pressure was 0.46 MPa. A proposed flexible pressure sensor based on an MoS2 film was also successfully used as a wearable pressure sensor to measure plantar pressure and demonstrated good repeatability. The results showed that the thin film pressure sensor had good piezoresistive performance and high sensitivity.

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Walek, S. D., M. S. Donley, J. S. Zabinski, and V. J. Dyhouse. "Characterization of pulsed laser deposited MoS2 by transmission electron microscopy." Journal of Materials Research 8, no. 11 (November 1993): 2933–41. http://dx.doi.org/10.1557/jmr.1993.2933.

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Molybdenum disulfide is a technologically important solid phase lubricant for vacuum and aerospace applications. Pulsed laser deposition of MoS2 is a novel method for producing fully dense, stoichiometric thin films and is a promising technique for controlling the crystallographic orientation of the films. Transmission electron microscopy (TEM) of self-supporting thin films and cross-sectional TEM samples was used to study the crystallography and microstructure of pulsed laser deposited films of MoS2. Films deposited at room temperature were found to be amorphous. Films deposited at 300 °C were nanocrystalline and had the basal planes oriented predominately parallel to the substrate within the first 12–15 nm of the substrate with an abrupt upturn into a perpendicular (edge) orientation farther from the substrate. Spherically shaped particles incorporated in the films from the PLD process were found to be single crystalline, randomly oriented, and less than about 0.1 μm in diameter. A few of these particles, observed in cross section, had flattened bottoms, indicating that they were molten when they arrived at the surface of the growing film. Analytical electron microscopy (AEM) was used to study the chemistry of the films. The x-ray microanalysis results showed that the films have the stoichiometry of cleaved single crystal MoS2 standards.

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Journal articles on the topic 'MoS2 characterization'

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