Controllable growth and electrostatic properties of Bernal stacked bilayer MoS2

Compared with the most studied monolayer MoS2, bilayer MoS2 possesses many distinct fascinating physical properties and potential applications owing to interlayer interactions and structural symmetry. Here, bilayer MoS2 domains with strict identical AB Bernal stacked order were controllably synthesized using chemical vapor deposition method. In addition, the electrostatic properties of bilayer MoS2 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 MoS2 is homogeneous across single crystals and polycrystalline films except for grain boundaries. However, the work function of the Bernal stacked bilayer MoS2 decreases by 50 ± 4 meV compared with that of monolayer MoS2 due to the interlayer coupling and screening effects. The deeper understanding gained here on the electrostatic properties of the AB Bernal stacked bilayer MoS2 should help in the creation of next-generation electronic and optoelectronic devices.