Efficient MoWO₃/VO₂/MoS₂/Si UV Schottky photodetectors; MoS₂ optimization and monoclinic VO₂ surface modifications

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Two-dimensional transition metal dichalcogenides (TMDs) like molybdenum disulfide (MoS₂) are promising semiconductors for optical and optoelectronic applications.
• Strongly correlated oxides offer unique properties for modulating TMD characteristics.

Purpose of the Study:

• To develop a scalable method for producing high-quality MoS₂ interfaced with monoclinic vanadium dioxide (VO₂).
• To investigate the structural, optical, and performance properties of MoWO₃/VO₂/MoS₂/Si photodetectors for UV detection.

Main Methods:

• Combined chemical vapor deposition (CVD) and physical vapor deposition (PVD) techniques for MoS₂ and molybdenum oxide layer deposition.
• Fabrication of MoWO₃/VO₂/MoS₂/Si photodetectors with varying sputtering times for MoS₂.
• Characterization using Raman spectroscopy, photoluminescence, and photocurrent measurements.

Main Results:

• MoWO₃/VO₂/MoS₂/Si with 60s MoS₂ deposition demonstrated efficient UV photodetection with high quality and excellent structural/absorption properties.
• The incorporation of VO₂ significantly altered photoluminescence intensity ratios and caused a redshift in MoS₂ Raman peaks.
• The optimized photodetector achieved a photocurrent gain of 1.6, detectivity of 4.32 × 10⁸ Jones, and quantum efficiency of ~1.0 × 10¹⁰ at 365 nm.
• A low-temperature semiconducting-metallic phase transition of VO₂ was observed around 40°C.

Conclusions:

• The novel CVD/PVD approach successfully integrates VO₂ with MoS₂ for enhanced photodetector performance.
• The MoWO₃/VO₂/MoS₂/Si structure exhibits superior UV detection capabilities due to optimized material quality and electronic coupling.
• The findings highlight the potential of strongly correlated oxides in tuning the optoelectronic properties of 2D semiconductors for advanced device applications.