Transitional metal dichalcogenides (TMDs) as a group of emerging two-dimensional layered semiconductors have great potential for device applications. Their layered structure allows various stacking combinations that can lead to almost endless possibilities of electrical properties. The screw dislocation-driven growth exhibited by TMDs also provides an opportunity to study edge defect states in order to improve solar cell efficiency. Tungsten dichalcogenides (WSe2, WS2) have received considerable attention for both solar energy harvesting and electronic applications. However, difficulties in fabricating thin film and complex heterojunctions suitable for investigation have limited their applications so far. We are using a combination of chemical vapor deposition (CVD), physical vapor deposition (PVD), and thermal annealing for tungsten dichalcogenides fabrication. We have been realized 50 μm WSe2 screw dislocation-driven plates (Fig. 1), 160 μm domain size monolayer WSe2 films (Fig. 2), and triangular WSe2 - WS2 lateral junctions. Physical characterization indicates our approach is a valid pathway for reliable tungsten dichalcogenide growth.

Investigation of fabrication methods for atomically-thin 2D tungsten dichalcogenides film, heterojunctions and devices

251st National Meeting (2016)

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