Controllable growth and electrostatic properties of Bernal stacked bilayer MoS2

Compared with the most studied monolayer MoS 2 , bilayer MoS 2 possesses many distinct fascinating physical properties and potential applications owing to interlayer interactions and structural symmetry. Here, bilayer MoS 2 domains with strict identical AB Bernal stacked order were controllably synthesized using chemical vapor deposition method. In addition, the electrostatic properties of bilayer MoS 2 were systematically investigated by multiple means of photoemission electron microscopy, electrostatic force microscopy, and kelvin probe force microscopy. We found that the work function of monolayer MoS 2 is homogeneous across single crystals and polycrystalline films except for grain boundaries. However, the work function of the Bernal stacked bilayer MoS 2 decreases by 50 ± 4 meV compared with that of monolayer MoS 2 due to the interlayer coupling and screening effects. The deeper understanding gained here on the electrostatic properties of the AB Bernal stacked bilayer MoS 2 should help in the creation of next-generation electronic and optoelectronic devices.