Wafer-scale and bi-layer MoS 2 films established through sequential mono-layer MoS 2 growth for device applications

Abstract Bi-layer molybdenum disulfide (MoS 2 ) films were prepared through sequential mono-layer MoS 2 growth using high temperature sulfurization of Mo oxide layers deposited by using the atomic layer deposition. An oxygen plasma treatment on the first MoS 2 layer will improve precursor distribution during the subsequent Mo oxide deposition, leading to a smoother second MoS 2 layer growth. Through the multi-stage sulfurization to enhance planar MoS 2 growth and depress Mo oxide segregation, uniform bi-layer MoS 2 films with improved crystallinity can be obtained. The bi-layer MoS 2 transistors exhibited a 42 times enhancement in field effect mobility compared with the mono-layer device. The sequential growth of mono-layer MoS 2 to achieve wafer-scale and bi-layer MoS 2 films provides a promising route for optimizing transistor performance toward practical applications.