Theoretical insights into the epitaxial growth of black arsenene enabled on GeS(001)

Black arsenene exhibits many exotic physical properties, such as Rashba spin-orbital coupling, fractional quantum Hall effect (Sheng 2021Nature59356) as well as some advantages in the field of energy storage (Wuet al2021J. Mater. Chem. A918793). High-quality and large-area BA monolayer can promote the investigations about BA and its device application. Epitaxial growth mechanism of BA is desirable. Here, based on density functional theory calculation, the epitaxial growth of BA monolayer was simulated. GeS(001) is found to be a suitable substrate for BA monolayer to epitaxially grow on. As a common isomer of arsenene, gray arsenene should be considered during the growth, because it is also energetically and thermodynamically stable in freestanding state. However, black arsenene monolayer is more energetically and thermodynamically stable than gray arsenene monolayer on GeS(001) substrate. During the growth, two arsenene atoms easily form a dimer on GeS(001), which diffuses more quickly and isotropically than arsenene monomer. In addition, the heterojunction consisted of balck arsenene and GeS(001) is an indirect gap semiconductor, but it can transform into a direct gap semiconductor with external tensile strain along zigzag direction. Remarkably, optical adsorption spectra range of BA/GeS(001) can be more abroad than that of BA and GeS(001) bilayers. The theatrical insights shed new light on some ideal substrates that can realize the epitaxial growth of high-quality simple substances of group V.