Self-Powered Broadband Photodetectors Based on WS₂-Anchored MoS₂ with Enhanced Responsivity and Detectivity

Self-powered broadband photodetectors utilizing 2D transition metal dichalcogenides (TMDs) are highly promising due to their remarkable light absorption capabilities and high sensitivity, making them suitable for applications such as military surveillance and wireless light detection systems. However, their performance is constrained by inadequate absorption, suboptimal charge carrier separation, and slow response times. In response to these limitations, the study fabricates a self-powered photodetector employing a heterostructure composed of WS₂ nanoparticles anchored to CVD-synthesized MoS₂, operating within the visible to near-infrared spectrum. The device demonstrates a responsivity of 283 mA W^-1 and a detectivity 6.44 × 10¹² Jones, alongside an external quantum efficiency of 61% under exposure of 580 nm. In comparison to pristine MoS₂, the MoS₂-WS₂ photodetector exhibited approximately 12-fold and 11-fold enhancements in responsivity and detectivity, respectively, in addition to fast response time of ≈375 µs and 6 ms. Additionally, density functional theory (DFT) calculations are used to analyze the increase in dark current that is observed following WS₂ nanoparticle anchored on MoS₂. This investigation highlights the potential of 2D heterostructures in the development of high-performance broadband photodetectors, which offer improved responsivity, stability, and self-powered operation for advanced optoelectronic applications.