Synthesis and Device Applications 2.5D Materials: Beyond 2D Materials with New Degrees of Freedom

The development of graphene research has opened a new field of atomically thin, 2D layered materials. They have unique properties, such as high carrier mobility, mechanical flexibility, optical transparency, and high thermal conductivity. We have been studying chemical vapor deposition (CVD) growth of high-quality 2D materials, such as graphene and hexagonal boron nitride (hBN). Here, we introduce our recent results based on a novel concept of “2.5-dimensional materials”. This concept expresses new degrees of freedom in 2D materials, such as materials, stacking angle, number of layers, and 2D nanospace between layers. In addition, the integration of 2D materials with other low-dimensional materials and practical applications of 2D materials to our life (3D), can be also regarded as 2.5D materials.