Defect-Polarization Coupling in 3D-Graphene/β-Ga₂O₃ Heterostructures for Self-Powered and Multifunctional Solar-Blind...

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Solar-blind ultraviolet photodetectors are crucial for secure communication and early warning systems.
• Monoclinic gallium oxide (β-Ga₂O₃) possesses an ultrawide bandgap, making it suitable for these applications.
• Oxygen vacancies in β-Ga₂O₃ are typically considered detrimental defects affecting device performance.

Purpose of the Study:

• To investigate the novel role of oxygen vacancies in enhancing optoelectronic properties of β-Ga₂O₃.
• To develop a 3D-graphene/β-Ga₂O₃ heterojunction for improved photodetector performance.
• To reframe oxygen vacancies as beneficial for device functionality.

Main Methods:

• Fabrication of a 3D-graphene/β-Ga₂O₃ heterojunction.
• Experimental characterization of the photodetector's performance.
• Density Functional Theory (DFT) and Technology Computer-Aided Design (TCAD) simulations.

Main Results:

• Oxygen vacancies induce local polarization, enhancing optical and electrical fields within the heterojunction.
• The heterojunction exhibits improved photogenerated carrier separation and transport.
• Achieved weak-light detection at 255 nm with high responsivity (3740 A/W) and detectivity (6.85 × 10¹³ Jones).
• Demonstrated zero-bias self-powered operation and a fast response time (140 µs).
• An 8x8 array enabled ultraviolet imaging and optical encrypted communication.

Conclusions:

• Oxygen vacancies can be leveraged as functional elements to enhance polarization in wide-bandgap semiconductors.
• The 3D-graphene/β-Ga₂O₃ heterojunction offers a promising pathway for advanced optoelectronic devices.
• This work opens new avenues for designing high-performance photodetectors for secure applications.