Self-driven high-performance broadband photodetector based on WSe2 nano-speckles

•Facile synthesis of WSe2 nano-speckles using sputtering and horizontal tube furnace.•WSe2-based high performance self-driven broadband (Vis- NIR) photodetector.•Highest responsivity under NIR illumination is achieved under photoconductive mode of operation. Long-term exposure to visible or infrared light may have harmful biological consequences, such as erythema, that can damage the cornea and retina. Additionally, trapped infrared light contributes to climate change on a global scale. Self-driven broadband photodetectors, which do not need an auxiliary battery and function in a multiband region of the electromagnetic spectrum, can be the solution to monitor such radiation. Though two-dimensional (2D) materials offer excellent optoelectronic characteristics, these materials still need to be fully explored to fabricate high-performance self-driven broadband photodetector. The study proposes nano-speckles like WSe2-based self-driven photodetection that operate in a broad spectral range from vis to NIR. The developed device exhibits 2.1 mAW−1 high responsivity at 860 nm illumination at zero bias (self-driven mode). Also, at zero bias a responsivity of 1.09 mAW−1 for 532 nm light illumination and 1.05 mAW−1 for 625 nm light illumination was obtained. Further, the device shows ultra-high responsivity of 1.2 × 104 mAW−1 and a very high external quantum efficiency of 2.84 × 103% with low noise equivalent power 3.27 × 10−13 WHz−1/2 at 860 nm light illumination under photoconductive mode. This report provides a promising simple synthesis method for fabricating a self-driven photodetection device that covers vis to NIR range with high sensitivity for future optoelectronic applications. [Display omitted]