Inspired by the unique optical and electronic properties of graphene, two-dimensional (2D) layered materials—as well as their hybrids—have been intensively investigated in recent years, driven by their potential applications in future electronic devices, nanocomposites, medical devices, photovoltaics, and thermoelectrics. The broad spectrum of atomic-layered crystals includes transition metal dichalcogenides (TMDs), semiconducting dichalcogenides, monoatomic buckled crystals such as black phosphorous (BP or phosphorene), and diatomic hexagonal boron nitride (h-BN). This class of materials can be obtained by exfoliation of bulk materials to small scales, or by epitaxial growth and chemical vapor deposition (CVD) for large areas. These atomically thin, single- or few-layer crystals are featured with strong intralayer covalent bonding and weak interlayer van der Waals bonding, resulting in superior electrical, optical, and mechanical properties.