High-Responsivity and Broadband MoS₂ Photodetector Using Interfacial Engineering.

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Combining molybdenum disulfide (MoS2) with silicon technology is key for high-performance photodetectors.
• Existing MoS2/silicon photodetectors struggle to achieve high responsivity, fast response, and broad spectral detection simultaneously.

Purpose of the Study:

• To develop a broad spectral n-type MoS2/p-type silicon heterojunction photodetector with improved performance.
• To investigate the effect of SiO2 dielectric layer pretreatment on photodetector characteristics.

Main Methods:

• Fabrication of an n-type MoS2/p-type silicon heterojunction photodetector.
• Pretreatment of the SiO2 dielectric layer on silicon substrate using soft plasma.
• Characterization of the photodetector's responsivity, response time, and spectral detection range.

Main Results:

• The pretreated SiO2 dielectric layer and silicon substrate formed a multilayer heterostructure with high carrier concentration and responsiveness.
• The MoS2/silicon photodetector demonstrated a responsivity of 4.05 × 10^4 A/W at 637 nm with a power density of 2 μW/mm^2.
• The device exhibited a broad detectable spectral range from 447 nm to 1600 nm.

Conclusions:

• The developed MoS2/silicon heterojunction photodetector overcomes previous limitations, offering high responsivity and broad spectral detection.
• The soft plasma pretreatment method is versatile and applicable to other n-type transition metal dichalcogenides (TMDCs) like MoTe2 and ReS2.