The electronic and optical properties of PC6/WS2 heterostructure modulated via biaxial strain and external electric field

Abstract

The significant electronic and optical properties of strain and external electric field modulated PC6/WS2 heterostructures are systematically explored by density functional theory (DFT) calculation. The stablest type B configuration of the heterostructure has Z-scheme mechanism with an indirect band gap of 0.93 eV and can conduct the overall water splitting. The absorption of the heterostructure is obviously enhanced in most of the visible light range compared with the constituent monolayers. The -8% ~ 8% biaxial strains can effectively adjust the band gaps and induce the band type transition of PC6/WS2 heterostructure from semiconductor (type II → I → II) to metal at the turning points of -4.43%, -1.15% and 4.71%, respectively. The tensile strains can increase the interfacial charge transfer, the dielectric constant ε(ω) and light absorption in the low energy range with respect to the compressive strains. The external electric fields (-0.80 ~ 0.80 V/Å) can also adjust the band alignments and band gaps, however, they cause the band type transition from metal to semiconductor (type II → I → II) at the turning points of -0.80, 0.08 and 0.60 V/Å, respectively. The interfacial charge transfer can be enhanced with the increasing of the positive and decreasing of the negative electric fields, whereas the ε(ω) is slightly affected and the light absorption is even adversely impacted by the electric fields. The conclusions could provide the theoretical guide for the potential application of PC6/WS2 heterostructure in the multifunctional optoelectronic devices.