GaN-Based Micro-Light-Emitting Diode Driven by a Monolithic Integrated Ultraviolet Phototransistor

In this letter, we report a monolithically photonic integrated device based on the configuration of an InGaN/GaN micro-light-emitting diode ( $\mu $ LED) in series with an AlGaN/GaN high-electron-mobility transistor (HEMT). As an ultraviolet phototransistor, the HEMT unit can act as both the optical and the electrical input ports of this integrated device. When the device is used as a transmitter, a 3-dB modulation bandwidth of approximate 300 MHz can be obtained. When the device is used as a receiver, a response time of < 10 ms and a responsivity of ~10⁷ A/W was demonstrated under 365 nm ultraviolet light. In addition, the received ultraviolet light signal can be converted into a higher-intensity visible light signal and emitted through the $\mu $ LED. The proposed monolithically integrated device shows great potential for on-chip optical interconnection and communication.