InGaN micro-LED array with integrated emission and detection functions for color detection application.

InGaN-based micro-LEDs can detect and emit optical signals simultaneously, owing to their overlapping emission and absorption spectra, enabling color detection. In this paper, we fabricated a green InGaN-based micro-LED array with integrated emission and detection functions. On the back side of the integrated device, when the 80 µm micro-LED emitted light, the 200 µm LED could receive reflected light to accomplish color detection. The spacing between the 80 µm and the 200 µm micro-LEDs was optimized to be 1 mm to reduce the effect of the direct light transmitted through the n-GaN layer without reflection. The integrated device shows good detection performance for different colors and skin colors, even in a dark environment. In addition, light can be emitted from the top side of the device. Utilization of light from both sides of the integrated device provides the possibility of its application in display, communication, and detection on the different sides.