Design and Photomodulation Performance of a UV-Driven Full GaN Integrated μLED and BJT Phototransistor

A vertical integration of indium gallium nitride/gallium nitride (InGaN/GaN)-based microlight-emitting diode (μLED) and GaN ultraviolet bipolar junction transistor (BJT) phototransistor (UVPT), based on the same GaN material and process platform (UVPT-μLED), was proposed. The integrated device is a novel integrated device with light-emitting, detecting, sensing, driving and regulating functions. It can be used as a receiver and transmitter. The light-emission effect of the μLED on UVPT can be regulated by changing the power of an external light. Optical-electrical-optical conversion was conducted with Silvaco TCAD software. Electro-optic modulation characteristics and optical power amplification were attained through a Silvaco TCAD simulation. By optimization of the size and concentration of the device epitaxial, the current gain of the optimized device reaches a maximum of 240. The UVPT-μLED device shows a strong response to small-power light and a stable response to high-power light. The UVPT-μLED chip with a high switching ratio was successfully prepared and used to verify the feasibility of the UVPT-μLED device. The proposed monolithic integrated device not only can be used for traditional displays but also shows great potential in intelligent displays, such as human–computer interactive systems, on-chip optical interconnects, photonic chips and visible-light communications.