High-performance deep ultraviolet photodetectors based on few-layer hexagonal boron nitride

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Hexagonal boron nitride (h-BN) is a graphene isomorph with unique properties.
• h-BN is explored as a substrate, dielectric layer, and for deep ultraviolet (DUV) optoelectronics.
• Its wide band gap and high absorption coefficient are key for DUV applications.

Purpose of the Study:

• To synthesize two-dimensional h-BN with controllable layers.
• To fabricate and characterize DUV photodetectors using synthesized h-BN.
• To evaluate the performance of h-BN based photodetectors for solar-blind applications.

Main Methods:

• Ion beam sputtering deposition was used to synthesize h-BN on Cu foils.
• h-BN layers were transferred onto SiO2/Si substrates for device fabrication.
• Photodetector performance was measured under DUV light illumination.

Main Results:

• Higher substrate temperatures during synthesis yielded h-BN with fewer domain boundaries and improved crystallinity.
• Photodetectors using a 3 nm h-BN layer achieved an on/off ratio exceeding 10^3 at 212 nm.
• A cutoff wavelength of approximately 225 nm was observed for the h-BN photodetectors.

Conclusions:

• Two-dimensional h-BN is a viable material for high-performance DUV optoelectronic devices.
• The synthesized h-BN layers demonstrate suitability for constructing solar-blind photodetectors.
• Controlled synthesis of h-BN is crucial for optimizing photodetector performance.