Suspended MoS Photodetector Using Patterned Sapphire Substrate.

The introduction of patterned sapphire substrates (PSS) has been regarded as an effective method to improve the photoelectric performance of 2D layered materials in recent years. Molybdenum disulfide (MoS ), an intriguing transition metal 2D materials with splendid photoresponse owing to a direct-indirect bandgap transition at monolayer, shows promising optoelectronics applications. Here, a large-scale, continuous multilayer MoS film is prepared on a SiO /Si substrate and transferred to flat sapphire substrate and PSS, respectively. An enhanced dynamic distribution of local electric field and concentrated photon excitons across the interface between MoS and patterned sapphire substrates are revealed by the finite-difference time-domain simulation. The photoelectric performance of the MoS /PSS photodetector is improved under the three lasers of 365, 460, and 660 nm. Under the 365 nm laser, the photocurrent increased by 3 times, noise equivalent power (NEP) decreases to 1.77 × 10 W/Hz and specific detectivity (D*) increases to 1.2 × 10 Jones. Meanwhile, the responsivity is increased by 7 times at 460 nm, and the response time of the MoS /PSS photodetector is also shortened under three wavelengths. The work demonstrates an effective method for enhancing the optical properties of photodetectors and enabling simultaneous detection of broad-spectrum emissions.