High-Performance MoS₂ Photodetectors Prepared Using a Patterned Gallium Nitride Substrate

Strain-adjusting the band gap of MoS₂ using patterned substrates to improve the photoelectric performance of MoS₂ 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 MoS₂ 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 MoS₂ 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 MoS₂ 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 MoS₂/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 × 10⁸ Jones. Our research has important guiding significance in adjusting the band gap of MoS₂ and enhancing the photoelectric performance of MoS₂ photodetectors.