Defect-engineering-enhanced electrical manipulation of anisotropic excitons in two-dimensional ReS2

Engineering the photoluminescence (PL) properties, such as emission peaks, intensity, and lifetime, is highly desirable for widespread applications. Electric control is a facile and feasible method, and electrical manipulation of the PL properties with a high efficiency becomes increasingly important. ReS2 has excellent environmental stability, distinctive interlayer decoupling, and strong anisotropic properties. Herein, taking ReS2 as a prototype material, we propose a novel strategy to enhance electrical control of anisotropic excitons in ReS2 by defect engineering. Sulfur vacancies have been introduced controllably by mild argon plasma treatment, and contribute to the anisotropic defect-related exciton emission whose polarization direction is almost the same as those of the excitons along the Re–S atomic chains. However, the conversion from the neutral excitons to the defect-related excitons significantly modulate the radiation recombination behavior under a lateral electric field. The defect-engineering-enhanced electrical manipulation of anisotropic excitons paves the way towards an exciton engineering in new 2D electronic and optoelectronic devices.