Voltage-tunable RGB emission from a single self-assembled InGaN nanocolumn LED

Abstract The integration of red-green-blue (RGB) light sources is essential for the development of high-resolution micro-light-emitting diode (micro-LED) displays. In this study, we propose a color-tunable device based on self-assembled InGaN-based nanocolumn LEDs without a patterning process. The nanocolumn LEDs exhibited a color shift from red to orange-yellow, pale green, and further to blue as the driving voltage increased. Micro-electroluminescence measurements revealed that a small wavelength shift was observed within individual nanocolumn regions. Instead, emission spots sequentially turned on, transitioning from red to blue (660-435 nm), elucidating the mechanism of color tuning. Combined with pulse-width-modulation driving, these findings open the pathway for the realization of novel monolithic RGB-LED devices.