Synthesis of vertically-aligned large-area MoS₂nanofilm and its application in MoS₂/Si heterostructure photodetector

Van der Waals heterostructures based on the combination of 2D transition metal dichalcogenides and conventional semiconductors offer new opportunities for the next generation of optoelectronics. In this work, the sulfurization of Mo film is used to synthesize vertically-aligned MoS₂nanofilm (V-MoS₂) with wafer-size and layer controllability. The V-MoS₂/n-Si heterojunction was fabricated by using a 20 nm thickness V-MoS₂, and the self-powered broadband photodetectors covering from deep ultraviolet to near infrared is achieved. The device shows superior responsivity (5.06 mA W^-1), good photodetectivity (5.36 × 10¹¹Jones) and high on/off ratioI_on/I_off(8.31 × 10³at 254 nm). Furthermore, the V-MoS₂/n-Si heterojunction device presents a fast response speed with the rise time and fall time being 54.53 ms and 97.83 ms, respectively. The high photoelectric performances could be attributed to the high-quality heterojunction between the V-MoS₂and n-Si. These findings suggest that the V-MoS₂/n-Si heterojunction has great potential applications in the deep ultraviolet-near infrared detection field, and might be used as a part of the construction of integrated optoelectronic systems.