SiC2/BP5: A pentagonal van der Waals heterostructure with tunable optoelectronic and mechanical properties

• The SiC 2 /BP 5 is a type-II indirect bandgap semiconductor (1.260 eV) and has high tunneling probability (21.17%). • The Poisson's ratio ( ν ) decreases with the compressive strain decreasing and the penta-BP 5 has negative ν under tensile strain. • Biaxial strain and E field can effectively induce the heterostructure transform from type-II to type-I and achieve semiconductor-metal transition. • The penta-SiC 2 and penta-BP 5 monolayers have excellent optical adsorption/reflection properties in ultraviolet and visible-light regions. • Current-voltage curve displays that the current magnitude can reach the order of 10 -3 μ A. The newly discovered semiconductor two-dimension (2D) materials with unique pentagon configurations of penta-SiC 2 and penta-BP 5 monolayers show interesting physicochemical properties. To expand the application fields of the pentagon 2D materials, we construct the SiC 2 /BP 5 heterostructures and investigate their electronic, mechanical, optical and transport properties based on the first-principles calculations. Our results indicate that the SiC 2 /BP 5 heterostructure and its individual components possess flexible tunability under biaxial strain. The Young’s modulus of these systems gradually decreases with the compressive (tensile) strain increasing and the penta-BP 5 exhibits negative Poisson's ratio at ε≥6%. The type-II SiC 2 /BP 5 heterostructure with an indirect bandgap (1.260 eV) shows great potential application in photoelectric devices. The tunneling probability of the heterostructure reaches 21.17%, promoting the carrier injection efficiency in the system. Biaxial strain and external electric field enable the type-II SiC 2 /BP 5 semiconductor to type-I or to metal. The optical properties of the SiC 2 /BP 5 heterostructure are a fit to its monolayers. Additionally, current-voltage curve displays that the heterostructure has small current (10 -3 μ A) with favorable application promising in digital integrated circuits. Our work provides a theoretical guidance for the fabrication and application of novel pentagon 2D materials.