Unusual Strain Dependence of Quasiparticle Electronic Structure, Exciton, and Optical Properties in Blue Phosphorene
Ju Zhou, Tianyi Cai, Sheng Ju
Abstract
By considering many-body effects explicitly, we study the quasiparticle electronic structure, exciton, and optical properties of two-dimensional (2D) material blue phosphorene and their evolution with biaxial strain. Although the pristine system is an indirect wide-band-gap semiconductor, it could evolve systematically toward an almost direct one when an intermediate tensile strain is applied. The absorption edge shows an obvious red shift with an increase in the lattice constant, enabling its access to a wide spectral range. Interestingly, when the band gap increases, the exciton binding energy decreases. This unusual relationship is found to be accompanied by an enhanced exciton effective mass and decreased dielectric screening with an increase in the lattice constant. Together with the evolution of the band edge, a funnel effect is revealed in the inhomogeneously strained 2D membrane of blue phosphorene. The gate-controlled carriers at the two sides could drift efficiently toward the center with maximum strain, where the relatively strong binding energy and short lifetime are beneficial for the realization of the emission of green and blue light.