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AIP Conference Proceedings [Author(s) INTERNATIONAL CONFERENCE ON SUSTAINABLE ENGINEERING AND TECHNOLOGY (ICONSET 2018) - Karnataka, India (19–20 April 2018)] - Synthesis of heterojunction layers of graphene/MoS2 and its characterization
摘要： The synthesis of atomically thin layered MoS2/Graphene heterostructure is of great interest in optoelectronic devices because of their unique properties. Herein, we present a synthesis method to prepare heterostructure of MoS2/graphene using low pressure chemical vapor deposition. Atomic force microscopy, Raman spectra demonstrated that MoS2 film on graphene exhibited good thickness uniformity. This novel sensing structure based on a 2D heterostructure promises to provide a simple route to an essential sensing platform for wearable electronics.
关键词： Heterojunction layer,Characterization,MoS2,Application,Graphene
更新于2025-09-04 15:30:14
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Charge transfer across monolayer/bilayer MoS<sub>2</sub> lateral interface and its influence on exciton and trion characteristics
摘要： The charge transfer phenomenon is identified to be a major factor determining exciton and trion characteristics of atomically thin MoS2 layers in various stacking configurations. We report photoluminescence (PL) from CVD-grown layered MoS2 in the presence of a skewed or a deformed triangular-shaped monolayer/bilayer (1L/2L) lateral interface. Integrated PL mapping images over the 1L and 2L MoS2 regions revealed that the neutral exciton emission was significantly enhanced and exhibited an oscillatory behavior in its intensity in the 1L region near the 1L/2L boundary, whereas the negative trion emission remained unchanged. The interplays among the number of MoS2 layers, a substrate, and a geometric boundary structure of the 1L/2L lateral interface turned out to be important in charge transfer due to a modulation in work functions. As a result, PL intensity profiles showed rich features such as a stacking dependent decomposition of excitons and trions, a sharp spectroscopic contrast along the 1L/2L boundary, and a charge transfer relevant to the work function difference at the lateral interface. Our results demonstrate that understanding the MoS2 PL is useful in characterizing the electronic properties in two-dimensional layered nanostructures and sheds light on possible new device applications.
关键词： density functional theory,work function,charge transfer,MoS2,exciton
更新于2025-09-04 15:30:14
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Total-Ionizing-Dose Response of MoS2 Transistors with ZrO2 and h-BN Gate Dielectrics
摘要： The total-ionizing-dose response of few-layer MoS2 transistors with ZrO2 or h-BN gate dielectrics is investigated under various bias conditions. Defects in MoS2 and surrounding dielectric layers significantly affect radiation-induced trapping. For devices with ZrO2 dielectrics, much larger negative Vth shifts and peak transconductance degradation are observed for irradiation under negative and ground bias than under positive bias. h-BN devices exhibit positive threshold voltage shifts under negative-bias irradiation. For both ZrO2 and h-BN passivated devices, the peak transconductance degradation results from charge trapping at the surface of the MoS2 or in nearby oxides. Changes in defect energy distributions of MoS2 FETs during X-ray irradiation are characterized via temperature-dependent low-frequency noise measurements. Density functional theory calculations are performed to provide insight into the pertinent defects.
关键词： DFT,MoS2 FET,low frequency noise,ZrO2,h-BN,2 dimension,X-ray
更新于2025-09-04 15:30:14
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The Post Annealing to Control the Number of Layers of 2D MoS2 and SnS2
摘要： We have demonstrated that post annealing could control the layer thickness of 2D MoS2 and SnS2 films transferred on a SiO2/Si substrate by varying the annealing temperature and time. Atomic force microscopy and Raman spectroscopy characterizations revealed that higher annealing temperature and longer treatment time led to thinner films, lower residues and fewer impurities on the surface of 2D materials. In addition, a higher possibility to attain few-layers on both 2D films was achieved using post annealing. The multiple layers of pristine films having the thickness over 15 nm were reduced down to bi-layers after annealing. We observed that the moderate annealing temperature of 450 °C on led to effective layer-thinning compared to the films annealed at 340 °C. The post annealing at 450 °C produced very smooth few-layers (≤4 nm thickness, >1 μm size) of 2D MoS2 and SnS2. However, the 2D films decomposed or disappeared at temperature greater than 650 °C. In addition, process time also affected the number of layers and the sweet spot turned out to be 2 to 3 hours in our experiment.
关键词： Annealing,Mechanical Exfoliation,Layer-Thinning,2D Materials,SnS2,MoS2
更新于2025-09-04 15:30:14
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Reversible and selective ion intercalation through the top surface of few-layer MoS2
摘要： Electrochemical intercalation of ions into the van der Waals gap of two-dimensional (2D) layered materials is a promising low-temperature synthesis strategy to tune their physical and chemical properties. It is widely believed that ions prefer intercalation into the van der Waals gap through the edges of the 2D flake, which generally causes wrinkling and distortion. Here we demonstrate that the ions can also intercalate through the top surface of few-layer MoS2 and this type of intercalation is more reversible and stable compared to the intercalation through the edges. Density functional theory calculations show that this intercalation is enabled by the existence of natural defects in exfoliated MoS2 flakes. Furthermore, we reveal that sealed-edge MoS2 allows intercalation of small alkali metal ions (e.g., Li+ and Na+) and rejects large ions (e.g., K+). These findings imply potential applications in developing functional 2D-material-based devices with high tunability and ion selectivity.
关键词： defects,MoS2,electrochemical control,two-dimensional materials,ion intercalation
更新于2025-09-04 15:30:14