Control of work function of MoS2 with ferroelectric polarization in honeycomb-like heterostructure

MoS2, one of the transition metal dichalcogenides (TMDs), has been utilized in heterostructures with functional oxide materials such as ferroelectrics. Here, we report MoS2-ferroelectric heterostructures, especially using the (111)-oriented PbTiO3 epitaxial thin films which have an unconventional polar axis. The mutual interplay between MoS2 and PbTiO3 is investigated via Kelvin probe force microscopy. On the ferroelectric thin films, an induced dipole effect is observed in MoS2, resulting in the variation of surface potential. From the surface potential, work function values of MoS2 are obtained on the ferroelectric polarizations. Also, a decrease and an increase in the work function of MoS2 are observed at in edge and interior regions, respectively. As a result, we performed an innovative approach to control the work function of MoS2 on the ferroelectric thin films. The honeycomb-like heterostructure consisting of MoS2 and PbTiO3 thin films gives the suggestion for the combination of TMDs and ferroelectrics, resulting in functional electronic devices.