Controlled two-step synthesis of nanostructured WS2 thin films for enhanced UV–visible photodetector applications

Abstract

Nowadays, development of transition metal dichalcogenides (TMDs) integrated ultra-fast optoelectronics devices under broad spectral range has attracted our research community. The fabricated devices should have high photoresponsivity, specific detectivity, fast switching, and low power consumption. Herein, we put the efforts to successfully synthesize a large area of WS 2 nanostructures using sputtering and chemical vapour deposition (CVD) techniques for ultraviolet-visible (UV-Vis) photodetector applications. It is found that following the sulfurization of sputter deposited tungsten films at 800 °C for 60 min facilitated nanostructures with high surface-area to volume ratio. Promising metal-semiconductor-metal (MSM) featured photodetector test-devices based upon interdigitated symmetric Ag electrodes are fabricated. Finally, interdigitated electrode structure, ohmic contact between metal and photoactive material, and enhanced structural properties allowed the test-device accelerates the photodetector performances with 100 ms of response time under UV and visible illuminations even at a bias voltage of 2 V. • WS 2 nanostructures are successfully grown by two-step synthesis process. • Fabricated the Ag/WS 2 /Ag UV-Vis photodetector with ohmic contact behavior. • Ultrafast response time of 100 ms was achieved through interdigitated Ag electrodes. • Superior figures of merit were achieved by the WS 2 photodetector.