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Enhanced electrocatalytic properties in MoS2/MoTe2 hybrid heterostructures for dye-sensitized solar cells
摘要： In this work, the hybrid bilayer of molybdenum disulfide (MoS2)/molybdenum telluride (MoTe2) was constructed on fluorine-doped tin oxide glass (FTO), and dye-sensitized solar cells (DSSCs) employing the material as counter electrode (CE) were implemented. The thickness of each layer of MoS2 and MoTe2 was tuned by changing the sputtering time to enhance DSSC performance. The DSSC with the MoS2/MoTe2 hybrid CE, exhibited a maximum power conversion efficiency (PCE) of 8.07% (6% for MoS2 and 7.25% for MoTe2 CE), and was comparable to one with Pt CE (8.33%). The observed good result of the MoS2/MoTe2 hybrid CE is ascribed to the synergistic properties between MoS2 and the metallic phase of MoTe2.
关键词： MoS2/MoTe2,DSSCs,Counter electrode,Hybrids
更新于2025-09-12 10:27:22
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Barkhausen effect in the first order structural phase transition in type-II Weyl semimetal MoTe <sub/>2</sub>
摘要： We report the first observation of the non-magnetic Barkhausen effect in van der Waals layered crystals, specifically, during transitions between the Td and 1T′ phases in type-II Weyl semimetal MoTe2. Thinning down the MoTe2 crystal from bulk material to about 25 nm results in a drastic strengthening of the hysteresis in the phase transition, with the difference in critical temperature increasing from ~40 K to more than 300 K. The Barkhausen effect appears for thin samples and the temperature range of the Barkhausen zone grows approximately linearly with reducing sample thickness, pointing to a surface origin of the phase pinning effects. The distribution of the Barkhausen jumps shows a power law behavior, with its critical exponent α = 1.27, in good agreement with existing scaling theory. Temperature-dependent Raman spectroscopy on MoTe2 crystals of various thicknesses shows results consistent with our transport measurements.
关键词： Barkhausen effect,2D materials,MoTe2,structural phase transition
更新于2025-09-11 14:15:04
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Fast identification of crystalline orientation of anisotropic two-dimensional materials using scanning polarization modulation microscopy
摘要： In this work, we have demonstrated that scanning polarization modulation microscopy (SPMM) provides a fast method for the identification of crystalline orientation of anisotropic two-dimensional (2D) materials. Using home-built 532 nm excited transmission SPMM, we identified the crystalline orientation of 2D orthorhombic black phosphorus, monoclinal 1T0-MoTe2, and triclinic ReS2 by measuring signals in only two incident polarization directions. So, it took just a few seconds to identify the crystalline orientation of anisotropic 2D materials. Our studies revealed that the SPMM method could be applied to arbitrary anisotropic 2D materials when selecting a suitable wavelength.
关键词： black phosphorus,1T0-MoTe2,scanning polarization modulation microscopy,anisotropic two-dimensional materials,ReS2,crystalline orientation
更新于2025-09-10 09:29:36
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Growth of 1T’ MoTe <sub/>2</sub> by Thermally-Assisted Conversion of Electrodeposited Tellurium Films
摘要： Molybdenum ditelluride (MoTe2) is a transition metal dichalcogenide (TMD) which has two phases stable under ambient conditions, a semiconducting (2H) and semimetallic (1T’) phase. Despite a host of interesting properties and potential applications, MoTe2 is one of the less-studied TMDs, perhaps due its relatively-low abundance in nature or challenges associated with its synthesis, such as the toxicity of most precursors. In this report, we describe the fabrication of thin films of phase-pure 1T’ MoTe2 using pre-deposited molybdenum and electrodeposited tellurium layers, at the relatively low temperature of 450?C. This method allows control over film geometry and over the tellurium concentration during the conversion. The MoTe2 films are characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy and electron microscopies. When applied as a catalyst for the hydrogen evolution reaction, the films display promising initial results. The MoTe2 films have a Tafel slope of below 70 mV dec-1 and compare favorably with other MoTe2 catalysts reported in the literature, especially considering the inherently-scalable fabrication method. The variation in electrocatalytic behavior with thickness and morphology of the films is also investigated.
关键词： 1T’ phase,thin-film,hydrogen evolution reaction,Raman spectroscopy,MoTe2,electrocatalysis
更新于2025-09-09 09:28:46
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Modulation of the electronic properties of two-dimensional MoTe2/WSe2 heterostructure by electrical field
摘要： The structure and electronic properties of two-dimensional MoTe2/WSe2 van der Waals heterostructure under external electric field have been investigated by first-principles calculation. The interlayer distance between MoTe2 and WSe2 is 3.613? and the binding energy per unit is ?0.183eV, which indicated that MoTe2 is bound to WSe2 via van der Waals interaction. The interlayer distance can be modified by external electric field and the band gap of MoTe2/WSe2 heterostructure continuously decreases with increasing external electric field, eventually a transition from semiconductor to metal is observed, particularly, the band alignment of the MoTe2/WSe2 heterostructure can be effectively tuned from intrinsic type-II to type-I. Applying external electric field along +z direction and ?z direction has different effects on the band gap due to the intrinsic spontaneous polarization in MoTe2/WSe2 heterostructure. Our study indicates that the external electric field can significantly tune the band offsets and modify the band alignment between MoTe2 and WSe2. The present study would be helpful for application of such transition-metal dichalcogenides heterostructures in nano- and optoelectronics.
关键词： band gap,MoTe2/WSe2 heterostructure,external electric field,Density of States
更新于2025-09-09 09:28:46
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Electric-field induced structural transition in vertical MoTe2- and Mo1–xWxTe2-based resistive memories
摘要： Transition metal dichalcogenides have attracted attention as potential building blocks for various electronic applications due to their atomically thin nature and polymorphism. Here, we report an electric-field-induced structural transition from a 2H semiconducting to a distorted transient structure (2Hd) and orthorhombic Td conducting phase in vertical 2H-MoTe2- and Mo1?xWxTe2-based resistive random access memory (RRAM) devices. RRAM programming voltages are tunable by the transition metal dichalcogenide thickness and show a distinctive trend of requiring lower electric fields for Mo1?xWxTe2 alloys versus MoTe2 compounds. Devices showed reproducible resistive switching within 10?ns between a high resistive state and a low resistive state. Moreover, using an Al2O3/MoTe2 stack, On/off current ratios of 106 with programming currents lower than 1?μA were achieved in a selectorless RRAM architecture. The sum of these findings demonstrates that controlled electrical state switching in two-dimensional materials is achievable and highlights the potential of transition metal dichalcogenides for memory applications.
关键词： Transition metal dichalcogenides,electric-field-induced structural transition,MoTe2,Mo1?xWxTe2,RRAM
更新于2025-09-04 15:30:14