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.