32 × 32 Pixelated High-Power Flip-Chip Blue Micro-LED-on-HFET Arrays for Submarine Optical Communication.

This work proposes the use of integrated high-power InGaN/GaN multiple-quantum-well flip-chip blue micro light-emitting diode (μ-LED) arrays on an AlGaN/GaN-based heterojunction field-effect transistor (HFET), also known as a high electron mobility transistor (HEMT), for various applications: underwater wireless optical communication (UWOC) and smart lighting. Therefore, we demonstrate high-power μ-LED-on-HEMT arrays that consist of 32 × 32 pixelated μ-LED arrays and 32 × 32 pixelated HEMT arrays and that are interconnected by a solder bump bonding technique. Each pixel of the μ-LED arrays emits light in the HEMT on-state. The threshold voltage, the off-state leakage current, and the drain current of the HEMT arrays are -4.6 V, <~1.1 × 10-9 A at gate-to-source voltage (VGS) = -10 V, and 21 mA at VGS = 4 V, respectively. At 12 mA, the forward voltage and the light output power (LOP) of μ-LED arrays are ~4.05 V and ~3.5 mW, respectively. The LOP of the integrated μ-LED-on-HEMT arrays increases from 0 to ~4 mW as the VGS increases from -6 to 4 V at VDD = 10 V. Each pixel of the integrated μ-LEDs exhibits a modulated high LOP at a peak wavelength of ~450 nm, showing their potential as candidates for use in UWOC.