A modified wrinkle-free MoS2 film transfer method for large area high mobility field-effect transistor.

Wrinkle-free transfer of chemical vapor deposition (CVD) synthesized 2D MoS2 is a prerequisite for large-area high-performance device fabrication. The surface-energy-assisted transfer method is a suitable method for MoS2 transfer, which greatly reduces the damage to the MoS2. However, in the process of tiling the MoS2 to the new substrate, droplets are sandwiched between the MoS2 and substrate, which are difficult to remove and easily cause wrinkles and cracks. To avoid the realization of wrinkles and cracks in the transfer, we developed a modified surface-energy-assisted transfer method that modifies the spreading parameter S of residual droplets sandwiched between the MoS2 and substrate. By using this strategy, the liquids were easily to remove from the MoS2/substrate interface resulting in a smooth MoS2 film with no wrinkles. Larger area back-gated field-effect transistor (FET) arrays were also fabricated based on the transferred monolayer MoS2 (10 × 10 mm) with atomic layer deposition prepared HfO2 as the high-k gate insulator. The FETs exhibited a high on/off ratio of 108 and carrier mobility up to 118 cm2 V-1 s-1, which is the highest mobility values reported for back-gate transistors fabricated with CVD synthesized MoS2. This transfer method provides a useful strategy for the fabrication of larger area high property FETs on MoS2.