| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系 === 106 === Two-dimensional transition metal dichalcogenides (TMDs) are one of the most promising material, especially in their heterostructure forms. The advantages of 2D TMDs not only come from their low dimensional structures but also the controllable electronic properties which are with fully potential in semiconductor or photoelectric applications.
We carry out first principles calculations to study conducting behavior of monolayer MoS2, WS2 and their heterostructures. The band structures, DOS and transmission spectra are used to analyze the electric properties of monolayer MoS2 and WS2. In the vertical heterostructures case, we discuss the relation between LDOS and transmission spectra under different stacking types and coverage ratio from 20% to 100%. In addition to vertical heterostructures, the carrier transmission along armchair or zigzag direction is calculated in lateral heterostructures.
Our results reveal that both monolayer MoS2 and WS2 are direct bandgap semiconductors. The AB1 and AA1 stacking types are more stable than AA3 in the vertical heterostructures and the AA1-100% has the highest transmission coefficient. The carrier shows better transmission along zigzag direction than armchair in the lateral heterostructures. Based on our calculations, we shows that their electronic properties depend on stacking types, coverage ratios or the transmission direction, which have multiple applications.
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