A 0D/0D WS2 Quantum Dot/CuO Nanoparticle Nanocomposite MSM Junction for High-Responsivity UV−Visible Photodetection

Abstract

The two-dimensional (2D) tungsten disulfide (WS2), a layered semiconductor, has shown considerable promise for ultraviolet−visible (UV−vis) photodetector (PD) development due to its exceptional photoelectrical conversion capabilities, particularly in the visible range. However, the thin film’s UV performance is constrained by suboptimal absorption efficiency, leading to the exploration of WS2 hybrids with other UV-sensitive materials to improve UV detection, but such hybrids often complicate fabrication, reduce response speed, or compromise visible sensitivity. Herein, we demonstrate a nanoscale heterostructure based on zero-dimensional (0D) quantum-confined WS2 quantum dots (WS2-QDs, average diameter ∼4.96 nm) blended with CuO nanoparticles (CuO NPs, average diameter ∼57.07 nm) to realize high-performance UV−visible photodetection using a simple, low-cost MSM architecture. The nanoscale blend exploits the strong quantum confinement and high surface-to-volume ratio of WS2-QDs together with the visible-light absorption of CuO NPs, creating numerous nanoscale heterointerfaces that enhance charge separation and carrier transport while simultaneously improving UV absorption without sacrificing visible-light sensitivity. The fabricated PD exhibits a broadband photoresponse over 365−660 nm at a low operating bias of −2.5 V, achieving a maximum responsivity of 86.52 A/W, an external quantum efficiency of 29395.5%, and a shot-noise-limited detectivity of 4.94 × 1013 Jones. Furthermore, the device demonstrates a rapid temporal response with rise/fall times of 64.48/68.53 ms, respectively.