Heterogeneous Integration of 20x10 µm Blue Micro-LEDs/Pixels on GaN HEMTs for Visible Light Communication

The development of next-generation communication networks aims to provide faster and more reliable solutions in a small form factor. Visible light communication (VLC) has emerged as a promising complementary technology to traditional radio frequency wireless communication due to its exceptional efficiency, high modulation speeds, and freedom from the congested radio spectrum. Recent advancements have focused on gallium nitride (GaN)-based micro-light-emitting diodes (microLEDs) for VLC. However, these microLEDs typically require high injection current densities and high-frequency operation, necessitating the use of independent drivers and resulting in bulky systems. This study presents an innovative approach to overcome these limitations by heterogeneously integrating of 20x10 µm² blue microLEDs using transfer printing onto a GaN-based high electron mobility transistor (HEMT) target wafer grown on silicon carbide (SiC) substrate. This integration allows for a compact, single-chip platform where the emission from a single microLED is modulated by tuning the gate voltage of its GaN HEMT. The resulting on-chip system achieves with a modulation bandwidth of 100 MHz, maintaining a small form factor. Our findings suggest that this approach holds significant promise for the development of future large-scale VLC systems on a single chip, offering broad application prospects.