Structural alignment of ZnO columns across multiple monolayer MoS₂ layers as compliant substrates

Understanding the behavior of materials in multi-dimensional architectures composed of atomically thin two-dimensional (2D) materials and three-dimensional (3D) materials has become mandatory for progress in materials preparation via various epitaxy techniques, such as van der Waals and remote epitaxy methods. We investigated the growth behavior of ZnO on monolayer MoS2 as a model system to study the growth of a 3D material on a 2D material, which is beyond the scope of remote and van der Waals epitaxy. The study revealed column-to-column alignment and inversion of crystallinity, which can be explained by combinatorial epitaxy, grain alignment across an atomically sharp interface, and a compliant substrate. The growth study enabled the formation of a ZnO/MoS2 heterostructure with type-I band alignment. Our findings will have a scientific impact on realizing 2D/3D heterostructures for practical device applications.