(515i) Stabilizing Phosphorene Via Hexagonal Boron Nitride Passivation

Layered crystals have revolutionized the field of nanoelectronics and optoelectronics due to their potential to be exfoliated (mechanically or chemically) into atomically-thin two-dimensional (2D) surfaces (for example graphene from graphite). Several 2D crystals and their complex van der Waals heterostructures are recently realized via micromechanical cleavage (peeling) technique. Phosphorene, a two-atom thick 2D material has found significant attention because of its unique properties including: sizable band gap (0.3-1.2 eV), in-plane anisotropy, and high charge carrier mobility. Further the 2D phosphorene layers can be easily exfoliated from the bulk 3D black phosphorous crystals and transferred onto any arbitrary substrates. However, the major problem associated with the technological applications of phosphorene is that these 2D material crystal structures can deteriorate in the ambient condition (in water or oxygen). Here, we stabilize the crystals of phosphorene by passivating with a 2D layer of hexagonal boron nitride (h-BN). Heterostructures of phosphorene and h-BN (h-BN/phosphorene/h-BN) were fabricated to remove lattice degradation of phosphorene from both the top and bottom surfaces. Confocal Raman vibrational spectroscopic results indicate that the h-BN/phosphorene/h-BN architecture (capsulated phosphorene) is more stable in contrast to the un-capsulated phosphorene (phosphorene/h-BN or phosphorene/SiO2). Interestingly, we observe that the structural degradation nucleates from the basal surfaces rather than edges or steps.