Structural and optical properties of MoS2 layers grown by successive two-step chemical vapor deposition method

• Demonstration of a two-step chemical vapor deposition approach for layered MoS2
• The crystallinity of the tri-layer MoS2 exhibits a 2H-MoS2 structure.
• The obtained MoS2 thin films could be easily transferred to SiO2/Si substrates.
• Back-gate field effect transistor using the synthesized MoS2 film was fabricated.

We have studied a successive two-step chemical vapor deposition (CVD) method to prepare large-scale MoS2 thin films using a horizontal hot wall furnace. The CVD growth was followed by evaporation of the MoO3 precursor on ~ 2.5 × 2.5 cm2 SiO2/Si substrates in the first step and a temperature ramp for sulfurization as a second step. Synthesized films were systematically analyzed by various structural and optical measurements. Crystallinity of the synthesized MoS2 tri-layer films exhibited a typical 2H-MoS2 structure and uniformly covered the whole substrate. MoS2 field effect transistors were fabricated by using the obtained CVD-MoS2, and these showed n-type behavior with an on/off ratio of about 103.