Unique low-energy line defects and lateral heterostructures in phosphorene

Defect engineering and heterostructure construction are important approaches to modulate the properties of two-dimensional semiconductors. We introduced four phosphorene allotropes as the defective structures to construct the corresponding line defects and lateral heterostructures in black phosphorene. In all the constructed phosphorene systems, the P atoms at the boundaries will keep local threefold covalent bonding, forming clean one-dimensional interfaces and exhibiting a high stability. Electronic structure calculations show that all the constructed structures are semiconducting in absent of deep defect states and the band gap values can be regulated by introducing different defective structures. Distinct distributions of the electronic frontier states are found in the different line defect systems and both type-I and II band alignments can be formed in the semiconducting lateral heterostructures.