Low-Pressure CVD Synthesis of Tetragonal Borophene Single-Crystalline Sheets with High Ambient Stability

Abstract

Being a typical graphene-like two-dimensional (2D) material, borophene has received a lot of attention due to its low density, high electron mobility, large Young's modulus, and good chemical stability. Compared with the corresponding bulk counterparts, 2D borophene has larger specific surface area, higher conductivity, and smaller work function, finding potential applications in high-speed transistors, optoelectronic detection, field emission (FE), and mechanical enforcement areas. In this paper, 2D tetragonal borophene sheets with high ambient stability have been successfully fabricated on the surface of 1 cm 2 copper foil using a developed low-pressure chemical vapor deposition (LPCVD) method. The vapor−solid mechanism was used to comprehend the formation of the tetragonal borophene sheets. The electrical conductivity of individual borophene sheets ranged from 4 to 5 × 10 −4 S/cm, and the band gap was about 2.1 eV, suggesting their narrow semiconductive nature. Also, the maximum FE current of individual borophene sheets was close to 1 μA, and their emission properties enhanced with the decreasing sheet thickness, comparable to many other nanomaterials with excellent FE performances. More interestingly, individual borophene sheets were found to retain good enough electrical transport and FE behaviors even if they experienced several days' atmospheric conservations. Our research results suggest that the LPCVD-grown borophene may be a promising building block for constructing high-performance nanodevices with good ambient stability.

Borophene nanomaterials: synthesis and applications in biosensors

“…Scalability and reproducibility have been reported to be difficult to achieve using the CVD process. 49 Hou et al first predicted hydrogenated borophene to be an ideal material for use in nanoelectronics due to its outstanding electronic and mechanical properties and good stability. They firstly successfully synthesized ultrastable hydrogenated borophene with semiconducting and crystalline properties using an in situ three-step thermal decomposition process.…”

“…Also, the nucleation process is very difficult to control for the production of uniform sheets with desired orientation, as the boron atoms are highly reactive. 49 Kehui et al fabricated 2D boron sheets through molecular beam epitaxy using an Al (111) surface as a substrate. Aluminum has three free electrons, which effectively compensates the electron deficiency in borophene.…”