Characterization of Interfaces Between ZnO and Monolayer MoS₂ in the Epitaxially Prepared Heterostructure

Integration of incommensurate materials has become more important along advances in next-generation microelectronics and quantum information systems because the advances are based on novel functionalities which are not usually obtained by size and shape controls of a single material. Incorporation of two-dimensional semiconducting materials for ultimately thin transport channels in transistors is a representative example of integration of incommensurate materials. For the heterogeneous materials integration, stacking and growth of crystalline two-dimensional materials/conventional materials have been intensively studied.<br/>Growth of crystalline materials on two-dimensional materials and vice versa is being considered as scalable and processing-compatible approach. However, the growth requires overcoming materials compatibility issue. Remote epitaxy based on lattice transparency across a two-dimensional material has been utilized as a solution to resolve the materials compatibility issue. As remote epitaxy research has been conducted in recent 7 years, understanding of interaction between the two-dimensional material and the overgrown layer has been expanded. The dominant mechanism of lattice transparency is being expanded by addition of other experimental observations, such as attenuative charge transfer. Most recent understanding of remote epitaxy mechanism implies that remote epitaxy is useful to control properties of the two-dimensional materials and the grown layers.<br/>Here, we present an example of interfacial phenomena induced by remote epitaxy. We prepared ZnO/monolayer MoS₂/ZnO heterostructure by remote epitaxy. The interface between ZnO and monolayer MoS2 was characterized by high-resolution scanning transmission electron microscopy, and four-dimensional scanning transmission electron microscopy. The atomic structure of the interface shows polarity inversion across the monolayer MoS₂. The inversion mechanism was explained by density functional theory calculation. Effects of the polarity inversion on microstructure and electronic properties were also investigated by cathodoluminescence microscopy.