Unveiling the Potential of Gold Nanoplasmonics Enhanced β-Ga ₂ O ₃ on Mica for Flexible Broadband Photodetectors

Flexible broadband photodetectors are crucial for the next generation of wearable and energy-efficient optoelectronic devices. These devices can facilitate applications in real-time health monitoring, environmental sensing, optical communication, and more. We fabricated a β-Ga 2 O 3 -based flexible self-powered photodetector on a mica substrate using a sputtering technique in this study. The device demonstrated a responsivity of 534 mA/W at 266 nm under 0 V applied bias. To broaden the operational wavelength range and enhance the sensitivity, we functionalized the β-Ga 2 O 3 film with gold nanoparticles (Au-NPs) utilizing the localized surface plasmon resonance effect of these nanoparticles. The functionalization significantly enhanced the photocurrent and extended the device’s response from deep-ultraviolet (UVC) to near-infrared (NIR) regions. The device with the Au-NPs functionalization demonstrated a >230% increase in responsivity, rising from 534 to 1241 mA/W at 266 nm. At an applied bias of 5 V, the functionalized device demonstrates impressive performance metrics: a high detectivity of 1.19 × 10 13 Jones, an ultrahigh responsivity of 7.8 × 10 4 mA/W, and a low noise-equivalent power of 4.11 × 10 –15 W Hz –1/2 for 266 nm light illumination. Furthermore, after 200 bending cycles, the flexible device retains 95% of its original photocurrent, showcasing its exceptional mechanical robustness. These advancements address the critical demand for flexible, broadband photodetectors and open avenues for wearable optoelectronic devices.