Atomic vacancy effects on enhanced photoresponse in 2D MoS2/VSe2 lateral heterostructure

The development of high-performance polarization-sensitive photodetectors is crucial for advancing optical communication, imaging systems, yet remains challenging due to fundamental limitations in conventional materials. This study presents a comprehensive investigation of vacancy-engineered MoS₂/VSe₂ van der Waals heterostructures for polarization-sensitive photodetection applications. Through systematic first-principles calculations and non-equilibrium Green's function methods, we demonstrate that strategic vacancy introduction enables precise control over both light absorption characteristics and photocurrent generation. The MoS₂/VSe₂ heterostructure exhibits remarkable spectral tunability, with single-atom vacancies inducing red-shifted absorption while double vacancies cause blue-shifts. Most notably, double-Se vacancies achieve a record 210 % photocurrent enhancement through suppressed carrier recombination, accompanied by exceptional polarization sensitivity (extinction ratio = 364.6 at 2.4 eV). Vacancy defects generate novel optoelectronic phenomena including reversible photocurrent switching under specific illumination conditions. These findings establish vacancy engineering as a powerful approach for developing next-generation polarized-light photodetectors with performance metrics surpassing conventional 2D material systems.