Air-Stable Self-Driven UV Photodetectors on Controllable Lead-Free CsCu₂I₃ Microwire Arrays

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• The Internet of Things (IoT) demands low-cost, self-powered ultraviolet (UV) photodetectors.
• Existing photodetector technologies face challenges in cost, power requirements, and performance for specific applications.

Purpose of the Study:

• To fabricate high-performance, self-driven UV photodetectors utilizing cesium copper iodide (CsCu2I3) microwire arrays.
• To investigate the impact of asymmetric metal-semiconductor-metal structures on photodetector performance.
• To evaluate the potential of CsCu2I3 as a material for passive, self-powered UV detection.

Main Methods:

• Fabrication of asymmetric metal-semiconductor-metal structures on large-area CsCu2I3 microwire arrays.
• Characterization of photodetector performance, including responsivity, photocurrent, dark current, and response speed.
• Assessment of device stability through repeated UV light switching cycles and long-term air storage.

Main Results:

• The asymmetric device design significantly enhanced photocurrent and response speed compared to symmetric structures.
• Achieved high responsivity (233 mA/W at 355 nm), open-circuit voltage (356 mV), and short-circuit current (372 pA) at 0 V bias.
• Demonstrated a high switch ratio (10^3) and excellent stability over 10,000 cycles and 90 days of air storage.

Conclusions:

• CsCu2I3 is a promising material for developing high-performance, self-powered UV photodetectors.
• Asymmetric device architecture is crucial for optimizing performance in self-driven UV detection.
• The fabricated photodetectors show significant potential for passive UV sensing applications.