Monolithic integration of p-MOSFETs with micro-LEDs on the same GaN LED epi

Digital control is an important topic for III-nitride LEDs. In this work, a p-channel MOSFET is monolithically integrated with a micro-LED by utilizing the same p-type GaN layer of a commercial blue LED wafer. The integrated device demonstrates a controllable electroluminescence by varying its gate-to-source and drain-to-source voltage. As for the integrated device, the p-MOSFET with a drain-to-source distance of 16 μm shows a maximum drain-to-source current of -1.4 mA/mm, a maximum transconductance of 123 μS/mm, and an on-off ratio of 3.5 × 10⁵.  The micro-LED with a diameter of 20 μm shows a uniform light emission, a 3.3 V forward voltage at 20 A/cm², and a low reverse leakage current of 4 × 10^-11 A at -5 V. This simple, easy, and cheap monolithic integration scheme enables another step forward for digital control of micro-LEDs by GaN CMOS circuitry in the near future, benefiting various applications such as microdisplay, visible light communications, and bio-sensing.