Searching the novel 2D semiconductor is crucial to develop the next-generation lowdimensional electronic device. Using first-principles calculations, we propose a class of unexplored binary V-V compound semiconductor (PN, AsN, SbN, AsP, SbP and SbAs) with monolayer black phosphorene (α) and blue phosphorene (β) structure. Our phonon spectra and room-temperature molecular dynamics (MD) calculations indicate that all compounds are very stable. Moreover, most of compounds are found to present a moderate energy gap in the visible frequency range, which can be tuned gradually by in-plane strain. Especially, α-phase V-V compounds have a direct gap while β-SbN, AsN, SbP, and SbAs may be promising candidates of 2D solar cell materials due to a wide gap separating acoustic and optical phonon modes. Furthermore, vertical heterostructures can be also built using lattice matched α(β)-SbN and phosphorene, and both vdW heterostructures are found to have intriguing direct band gap. The present investigation not only broads the scope of layered group V semiconductors but also provides an unprecedented route for the potential applications of 2D V-V families in optoelectronic and nanoelectronic semiconductor devices. Keywords: monolayer compound semiconductor, electronic properties, phosphorene, firstprinciples
I. INTRUDUCTIONTwo-dimensional (2D) semiconductors of group V elements including phosphorene, arsenene, and antimonene have been rapidly attracting interest on account of their significant wide-range fundamental band gap, high and anisotropic carrier mobility, linear dichroism, and anisotropic thermal conductivities.1-11 The outstanding properties make these systems as very favorable contenders for 2D electronics applications beyond graphene and transition metal dichalcogenides (TMDs).12-14 The success of group V monolayer motivates the ongoing search for related 2D materials with unusual properties. Recently, phosphorene has been extended notably by introducing isoelectronic IV-VI compounds, 15,16 it is thus intriguing to see whether the binary V-V compound monolayers can be achieved.As established in case of phosphorus, group V elements and their compounds can form interesting 2D layered structures such as black-phosphorene-like [α-phase, (No.64)] and blue-phosphorene-like [β-phase, (No.166)], in which the atomic layers are binding with vdW interaction. It's well known that graphene and phosphorene can be mechanically exfoliated from graphite and bulk black phosphorus.17 It is thus viable that the layered black-phosphorene-like (α-phase) and blue-phosphorenelike (β-phase) of AsP and SbAs structures can be made into monolayer AsP and SbAs.18 Very recently, Kou et al. have investigated monolayer arsenic and its compound SbAs, which can be seen as a single-layer of bulk compound with space group of R3m. Except SbAs, P, As and Sb can also be pairwise combined to form various binary compounds. It is expected that these binary V-V materials will exhibit unforeseen properties that present invaluable opportunities for ...
