Chemical vapor deposited WS2/MoS2 heterostructure photodetector with enhanced photoresponsivity

Abstract Two-dimensional transition metal dichalcogenides (TMDCs) have attracted great interest due to their unique semiconductor properties. Among all TMDC materials, MoS 2 and WS 2 are promising for composing heterostructures. However, traditional TMDC heterostructure fabrication depends on transfer process, with drawbacks of interface impurity and small size. In this work, a two-step chemical vapor deposition (CVD) process was applied to synthesize large-scale WS 2 /MoS 2 heterostructure. Surface morphology and crystal structure characterizations demonstrate the high-quality WS 2 /MoS 2 heterostructure. The WS 2 /MoS 2 heterostructure photodetector fabricated by photolithography exhibits an enhanced photoresponsivity up to 370 A W −1 in comparison with single WS 2 or MoS 2 devices. This study suggests a direct CVD growth of large-scale TMDC heterostructure films with clean interface. The built-in electric field at interface contributes to the separation of photo-generated electron–hole pairs, leading to enhanced photocurrent and responsivity, and showing promising potentials in photo-electric applications.