Significant Enhancement of the Stark Effect in Rippled Monolayer Blue Phosphorus

We explore the impact of a vertical electric field on the electronic properties of rippled monolayer blue phosphorus (blue-P). On the basis of density functional theory calculations, we demonstrate electric field-induced splitting and shifting of the energy levels of rippled blue-P, similar to the Stark effect in atomic energy levels. The band gap of rippled blue-P is found to decrease linearly either with increasing electric field strength for a fixed ripple height or with increasing ripple height for a fixed electric field strength. The application of a transverse electric field also leads to a spatial separation of the conduction and valence band states near the bottom and the top of the ripple, respectively. The demonstrated Stark effect in rippled blue-P offers a potent band gap engineering tool, and it may open a gateway for possible electronic and optoelectronic applications.