Photoresponse properties of large area MoS2 metal-semiconductor-metal photodetectors

In this study, a large-area molybdenum disulfide (MoS2) thin film was obtained by low pressure thermal sulfurization. Raman scattering spectrum shows that the peaks at 374 and 403 cm(-1) are from the MoS2 thin film. XRD result reveals peaks at 33 and 58.5 degrees indicating MoS2(100) and (110) crystal planes. By using gold (Au), silver (Ag), and aluminum (Al) as contact materials on the MoS2 thin film, photoresponsivity results indicate that Ag is a suitable material for obtaining a high responsivity for a high-performance photodetector (PD). Photocurrent mapping measurements also reveal that Ag contacts have the best carrier transport characteristic with carrier diffusion length of 101 mu m among these contacts. Furthermore, we investigated metal-semiconductor-metal MoS2 thin film PDs with interdigitated fingers of 300, 400, 500, and 600 mu m contact widths, which showed that the large contact widths could produce a high photoresponse for PD application owing to low resistance. (C) 2018 The Japan Society of Applied Physics.