Au/WS₂-QDs/Au MSM Junction for a Cost-Effective & Efficient Visible Blind UV-A Photodetection

The rapid growth of recently discovered materials, such as transition metal dichalcogenides (TMDs), has enabled the development of high-performance UV photodetectors (PDs). Despite considerable research on TMDs-based UV PDs, high-performance visible blind UV-A PDs are still needed due to their requirement for exposure analysis in growing Internet of Things (IoT) based wearables and protection against UV-A radiation. Therefore, the fabrication of easy and inexpensive hydrothermally synthesized Au/WS ₂ -QDs/Au MSM visible blind UV-A PD is reported in this article. The fabricated PD demonstrated an excellent response to a 365 nm UV-A light of 5 μW/cm ² intensity with a UV to Vis rejection ratio (R _365nm /R _460nm ) of ~472.5, owing to the high absorption efficiency of WS ₂ -QDs and gain associated with short channel MSM structure. The fabricated PD obtained responsivity of 58.93 A/W, EQE of 20019.21%, and detectivity of 4.27 x 10 ¹³ Jones at an operating voltage of 2.5 V. The device also exhibited fast speed with rise and fall times of 78 ms and 82 ms.