Synergistic Pyro-Phototronics and Structural Anisotropy in CsAg₂I₃/GaN Heterostructures for High-Performance...

Area of Science:

• Optoelectronics and Nanomaterials Science
• Solid-State Physics and Device Engineering

Background:

• Ultraviolet (UV) photodetectors are crucial for secure communication and sensing, but face challenges in material stability, interfacial losses, and multifunctional integration.
• Existing materials often struggle with stability, symmetry limitations, and achieving combined spectral selectivity, self-powered operation, and polarization sensitivity.

Purpose of the Study:

• To develop a novel van der Waals (vdW) heterojunction for high-performance UV photodetectors.
• To integrate in-plane structural anisotropy and the pyro-phototronic effect for enhanced device functionality.
• To overcome limitations of conventional perovskites and wide-bandgap semiconductors in UV detection.

Main Methods:

• Synthesis of CsAg2I3 single-crystals via chemical vapor deposition (CVD).
• Fabrication of a CsAg2I3/GaN vdW heterojunction device.
• Characterization of material properties (bandgap, pyroelectricity, nonlinear response) and device performance (dark current, responsivity, detectivity, response speed, dichroic ratio).

Main Results:

• The CsAg2I3/GaN heterojunction exhibits a wide bandgap (~3.38 eV), strong pyroelectricity, and an atomically sharp interface.
• The device achieved record-breaking performance: ultralow dark current (0.3 pA), high responsivity (0.28 A/W), detectivity (1.7 × 10^12 Jones), and ultrafast response (16/21 µs).
• The pyro-phototronic effect significantly enhanced polarization sensitivity, yielding the highest dichroic ratio (10.5) for all-inorganic perovskite systems.

Conclusions:

• The CsAg2I3/GaN vdW heterojunction offers a stable, high-performance platform for self-powered, polarization-sensitive UV optoelectronics.
• This work establishes a new paradigm for synergizing pyro-phototronics and structural anisotropy in heterostructures for advanced sensing and communication.
• The device demonstrated exceptional stability and potential for real-world applications, including information-splitting encryption systems.