One-step H₂S reactive sputtering for 2D MoS₂/Si heterojunction photodetector

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• High-throughput, large-area fabrication of 2D transition metal dichalcogenide (TMC) devices is crucial for their commercialization.
• Existing methods for growing 2D materials like molybdenum disulfide (MoS2) on conventional substrates often face challenges with material quality and scalability.

Purpose of the Study:

• To develop a reactive sputtering technique for direct growth of high-quality 2D MoS2 on semiconductor substrates.
• To compensate for sulfur deficiencies during MoS2 sputtering and improve material stoichiometry and quality.
• To fabricate and characterize a 2D MoS2/p-Si heterojunction photodevice using the developed method.

Main Methods:

• Reactive sputtering of MoS2 using H2S gas molecules.
• Sequential in situ post-annealing treatment within the same sputtering chamber.
• Characterization using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and UV-visible spectroscopy.
• Fabrication and testing of MoS2/p-Si heterojunction photodetectors.

Main Results:

• The Ar/H2S sputtering method significantly improved the stoichiometry and quality of MoS2 films compared to Ar-only sputtering.
• MoS2 films deposited using Ar/H2S exhibited lower defect densities.
• The fabricated Ar/H2S MoS2 photodiode demonstrated improved performance.
• Optimal photodetector performance was achieved within a deposited MoS2 thickness range of 8-12 nm.

Conclusions:

• Reactive sputtering with H2S and in situ annealing is an effective technique for producing high-quality 2D MoS2 films on semiconductor substrates.
• This method enables high-throughput, large-area fabrication suitable for competitive 2D TMC devices.
• The optimized MoS2/p-Si photodetector shows promise for advanced optoelectronic applications.