ABSTRACT

Black phosphorus is the most thermodynamically stable and densest allotropes under ambient temperature and pressure. It can be synthesized by heating several other forms of phosphorus under high pressure above 10 kbar. The atomic-scale microscopic study shows that the decomposition starts from forming eye-shaped cracks along the [001] direction, producing an amorphous red phosphorus–like skeleton in the end. Bulk white phosphorus, grown by the P4 vapor condensation, has a cubic form containing 58 tetrahedral P4 molecules in the unit cell. Structural characterization of red phosphorus is difficult compared to black and white phosphorus due to its tendency to form polymeric amorphous structures. Hittorf’s phosphorus was first discovered by W. Hittorf in 1865. The chapter discusses to show the effect of anisotripic structure on the phononic properties, the anisotropy of the acoustic phonon and its strain modulation. The knowledge of defect formation, healing, and migration of phosphorene is helpful for understanding the thermally activated process and protecting the structural integrity.