Vertical Barrier Heterostructures for Reliable, Robust, and High-Performance Ultraviolet Detection

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Low-dimensional material photodetectors often exhibit unreliable photoresponse dependent on optical power, especially in the ultraviolet spectrum.
• Barrier photodetectors offer a reliable strategy by selectively allowing high-energy photocarriers while blocking low-energy ones.

Purpose of the Study:

• To report on vertical barrier heterostructure photodetectors (VBHPs) for robust and high-performance ultraviolet detection.
• To investigate the performance characteristics of VBHPs utilizing graphene, MoS2, and h-BN.

Main Methods:

• Fabrication of VBHPs using a graphene bottom electrode, MoS2 light absorber, and h-BN energy barrier.
• Characterization of VBHPs, including noise current, photoresponse stability, responsivity, photo on-off ratio, and detectivity at various wavelengths and temperatures.

Main Results:

• Achieved ultralow noise current (1.69 × 10^-15 A Hz^-1/2) and stable photo on/off states (>10^4 cycles).
• Demonstrated light power-independent high responsivity (416.2 mA W^-1 at 360 nm) and a high photo on-off ratio (1.2 × 10^5 at 360 nm).
• Measured high detectivities (3.2 × 10^10 Jones at 266 nm, 9.9 × 10^10 Jones at 360 nm) and wide linear dynamic ranges.

Conclusions:

• The asymmetric band barrier distribution at the MoS2/h-BN interface is key to the VBHPs' superior performance.
• VBHPs demonstrate significant potential for developing new types of reliable ultraviolet detectors.