Dual-mode operation of GaN-based p-i-n diodes for electroluminescent emission and self-powered photodetection

The integration of light-emitting displays and photodetectors into a single device is increasingly attractive for the development of multifunctional and energy-efficient systems. In this study, we present a gallium nitride (GaN) based photodetection light-emitting diode (pdLED) capable of dual-mode operation through simple bias control. Under forward bias, the pdLED functions as an efficient light emitter, achieving a peak external quantum efficiency (EQE) and a wall plug efficiency (WPE) of 21.6% and 20.3%, respectively. When stimulated by an external light signal under zero bias, this device can operate as a self-powered photodetector and generate a photocurrent. The pdLED demonstrates a wide spectral response ranging from the ultraviolet to visible light and achieves a peak responsivity of up to 200 mA/W. In addition, the device is able to maintain high responsivity even under weak illumination. Finally, we constructed an integrated chip featuring pdLED arrays to successfully detect and image optical signal graphics, enhancing the competitiveness of future multifunctional sensing and display systems.