Nitrogen-doped graphene quantum dots (N-GQDs) for high-performance self-powered UV photodetectors

Abstract

This study presents the fabrication and characterization of a self-powered ultraviolet (UV) photodetector based on nitrogen-doped graphene quantum dots (N-GQDs) as the active material, integrated into a lateral metal–semiconductor–metal (MSM) device configuration. Here, the N-GQDs were synthesized via the pulsed laser ablation (PLA) method. The as-prepared N-GQDs were investigated through structural, optical, and electrical characterizations, confirming their nitrogen incorporation and high crystallinity, strong ultraviolet absorption and efficient charge transport. A UV photodetector fabricated with as-synthesized N-GQDs exhibits excellent performance under 365 nm illumination, including strong photocurrent (61.25 μA) with negligible dark current (1.7 μA) at +1 V, high responsivity (0.25 A/W), detectivity (1.05 × 1011 Jones), and external quantum efficiency (84%). Transient measurements reveal rise (264 ms) and decay (293 ms) times with stable, repeatable operation at zero bias voltage, confirming self-powered capability. This study demonstrates the promising use of N-GQDs as a key material for self-powered UV photodetectors, opening new avenues for next generation flexible, low cost, and energy-efficient optoelectronic devices. Further improvements in device optimization and integration with other materials can enhance performance and broaden the scope of applications, including wearable electronics, environmental monitoring, and security systems.