Synthesis of continuous MoS2:Er films and their enhanced NIR photoresponse for photo communication

Abstract

Enhancing the near-infrared (NIR) photoresponse of molybdenum disulfide (MoS₂) is essential for its photoelectric applications including photo communication. Herein, continuous Er-doped MoS₂ (MoS₂:Er) films were synthesized via a multi-step process. The enhanced NIR response of MoS₂:Er at 808 nm and 980 nm is attributed to the characteristic absorption of Er³⁺ at both wavelengths and the increased traps introduced by Er-doping. The developed MoS₂:Er/SiO₂/p-Si heterojunction device possesses a rapid response time of ∼1.4 μs, a high detectivity of ∼3.67 × 10¹⁰ Jones, and a wide 3 dB bandwidth of 7.9 kHz at −0.5 V under 980 nm laser irradiation. The dark current of the heterojunction photodetector can be suppressed under 980 nm laser illumination for a period longer than 8 ms because of an extra light-generated field in the dark induced by the residual charges in the traps. Meanwhile, a NIR light communication system is demonstrated by employing the heterojunction detectors as the receiver. This work provides an alternative method to synthesize homogeneous metal-doped MoS₂ films and an effective strategy to modulate the photoelectric performance of MoS₂-based devices.