- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Direct Synthesis of a Self‐Assembled WSe <sub/>2</sub> /MoS <sub/>2</sub> Heterostructure Array and its Optoelectrical Properties
摘要： Functional van der Waals heterojunctions of transition metal dichalcogenides are emerging as a potential candidate for the basis of next-generation logic devices and optoelectronics. However, the complexity of synthesis processes so far has delayed the successful integration of the heterostructure device array within a large scale, which is necessary for practical applications. Here, a direct synthesis method is introduced to fabricate an array of self-assembled WSe2/MoS2 heterostructures through facile solution-based directional precipitation. By manipulating the internal convection flow (i.e., Marangoni flow) of the solution, the WSe2 wires are selectively stacked over the MoS2 wires at a specific angle, which enables the formation of parallel- and cross-aligned heterostructures. The realized WSe2/MoS2-based p–n heterojunction shows not only high rectification (ideality factor: 1.18) but also promising optoelectrical properties with a high responsivity of 5.39 A W?1 and response speed of 16 μs. As a feasible application, a WSe2/MoS2-based photodiode array (10 × 10) is demonstrated, which proves that the photosensing system can detect the position and intensity of an external light source. The solution-based growth of hierarchical structures with various alignments could offer a method for the further development of large-area electronic and optoelectronic applications.
关键词： transition-metal dichalcogenides,p–n junctions,Marangoni flow,photodetectors,heterojunctions
更新于2025-09-11 14:15:04
-
Multicomponent multiphase modeling of dissimilar laser cladding process with high-speed steel on medium carbon steel
摘要： During a laser cladding process, the transport phenomena in the molten pool, including rapid solidification, strong fluid convection, and species diffusion are complex, and determine the microstructure and composition of the cladding layer. In this study, a three-dimensional transient multicomponent multiphase model was proposed to simulate the dissimilar laser cladding process with T15 powder and T15/CeO2 mixed powder on 42CrMo substrate. The position and expression of the source terms on energy and mass were clearly defined. The model was validated by comparing the morphology of the cross section with single-track cladding experiments. The simulation results indicate that the molten pool is dominated by a strong Marangoni flow that results in a fully mixed cladding layer and a narrow transition zone at the bottom. The molten pool exhibits an inward flow pattern with pure T15 powder and an outward flow pattern with T15-CeO2 mixed powder. The content of the elements and the microstructure of the cladding layer were investigated by using an electron probe micro-analyzer and a scanning electron microscope. The microstructure evolves from planar to cellular, and to equiaxed dendrites from the substrate–clad interface to the top surface. The transition zone comprised of planar and cellular grains. The solidification characteristics calculated from the numerical model were associated to the grain morphology.
关键词： Transport phenomena,Grain morphology,Laser cladding,Multiphase modeling,Marangoni flow
更新于2025-09-11 14:15:04