Monolithic Integration of GaN-Based Green Micro-LED and Quasi-Vertical MOSFET Utilizing a Hybrid Tunnel Junction

We demonstrated the monolithic integration of GaN-based driving metal-oxide-semiconductor field effect transistor (MOSFET) on micro-light-emitting diodes (LEDs) by regrowing a hybrid tunnel junction (TJ) on top of a commercial green LED wafer. The hybrid TJ served not only as the current spreading layer for LEDs, but the n/p/n structure of the LED + TJ stack could also be utilized for fabricating a quasi-vertical driving MOSFET. The LED was connected to the MOSFET via the conductive n-GaN layer. By modulating the gate supply voltage, the MOSFET effectively controlled the injection current of the LED, allowing for precise modulation of its output performance. The integrated 60- m~ LED exhibited a high output power of 0. 12 mW (~4. 2 W/cm 2) at a current of 0. 3 mA (around 10 A/cm 2) when the MOSFET was modulated with V ₃₃ = 5 V and V ₆ = 16 V, demonstrating good LED performance and comparable driving capability to previous GaN-based MOSFETs and oxide-based thin film transistors. This work provides a new method for GaN FET/LED monolithic integration, which paves the way for potential applications in visible light communication and flexible LED displays.