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 (MoS2), 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 MoS2 film is prepared on a SiO2/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 MoS2 and patterned sapphire substrates are revealed by the finite‐difference time‐domain simulation. The photoelectric performance of the MoS2/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 × 10−14 W/Hz1/2 and specific detectivity (D*) increases to 1.2 × 1010 Jones. Meanwhile, the responsivity is increased by 7 times at 460 nm, and the response time of the MoS2/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.

Strain-adjusting the band gap of MoS 2 using patterned substrates to improve the photoelectric performance of MoS 2 has gradually become a research hotspot in recent years. However, there are still difficulties in obtaining high-quality two-dimensional materials and preparing photodetectors on patterned substrates. To overcome this, a continuous multilayer MoS 2 film was transferred to a patterned gallium nitride substrate (PGS) for the fabrication of photodetectors, and density functional theory calculations showed that the band gap of the MoS 2 film increased and that the electron effective mass decreased due to the introduction of PGS. In addition, finite difference time domain simulation showed that the electric field in the MoS 2 area on the PGS is enhanced compared with that on the flat gallium nitride substrate due to the enhanced light scattering effect of the PGS. The photoresponse of the MoS 2 /PGS photodetector at 460 nm was also enhanced, with I ph increasing by 5 times, R increasing by 2 times, NEP decreasing to 3.88 × 10 −13 W/Hz 1/2 , and D* increasing to 5.6 × 10 8 Jones. Our research has important guiding significance in adjusting the band gap of MoS 2 and enhancing the photoelectric performance of MoS 2 photodetectors.

Strain regulation as an effective way to enhance the photoelectric properties of two-dimensional (2D) transition metal dichalcogenides has been widely employed to improve the performance of photovoltaic devices. In this work, tensile strain was introduced in multilayer MoS 2 grown on GaN by depositing 3 nm of Al 2 O 3 on the surface. The temperature-dependent Raman spectrum shows that the thermal stability of MoS 2 is improved by Al 2 O 3 . Theoretical simulations confirmed the existence of tensile strain on MoS 2 covered with Al 2 O 3 , and the bandgap and electron effective mass of six layers of MoS 2 decreased due to tensile strain, which resulted in an increase of electron mobility. Due to the tensile strain effect, the photodetector with the Al 2 O 3 stress liner achieved better performance under the illumination of 365 nm wavelength, including a higher responsivity of 24.6 A/W, photoconductive gain of 520, and external quantum efficiency of 8381%, which are more than twice the corresponding values of photodetectors without Al 2 O 3 . Our work provides an effective technical way for improving the performance of 2D material photodetectors.

Strain engineering has been reported to improve the optical and electrical properties of two-dimensional materials, and the adjustable bandgap of MoS2 has great application value in strain engineering. In this work, to explore the influence of the Si3N4 stress liner on the MoS2 photodetector, plasma enhanced chemical vapor deposition was used to deposit a 5 nm Si3N4 film on the surface of the device to introduce strain. The simulation results show that there is tensile strain in the MoS2 area under a Si3N4 layer, which can decrease the bandgap and electron effective mass of MoS2. The measurement results of the device show that the Si3N4 stress liner devices exhibit a higher light response than the Al2O3/MoS2/sapphire photodetector (control devices) under 365 and 460 nm laser illuminations. The maximum photocurrent (Iph) and responsivity (R) of the stress liner device under 365 nm illumination are 4.1 mA and 739.9 A/W, respectively, which are more than 30 times the corresponding value of the control device. Also, the maximum specific detectivity (D*) reached 2.5 × 1011 Jones, and the lowest noise equivalent power is 8.7 × 10−16 W/Hz1/2. Our work proved the feasibility of the Si3N4 stress liner to improve the performance of MoS2 photodetectors.

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