Linearly polarized light emission from GaN micro-LEDs for 3D display

A three-dimensional (3D) display provides an immersive user experience and represents the frontier of display technology. The 3D display based on polarizer films is relatively mature. However, the currently used polarizer films lead to bulk systems and low efficiency. Micro-light-emitting diodes (micro-LEDs) have the advantages of small size, high contrast, low power consumption, and high response frequency. The 3D micro-LED displays combine the characteristics of 3D display and the advantages of micro-LEDs simultaneously, which can be used in portable electronics or micro-LED projectors and provides users with 3D experience. Here, linearly polarized (LP) micro-LEDs with varied chip diameters are numerically and experimentally investigated. Subwavelength metal gratings are integrated directly on the p-GaN of micro-LEDs. A maximum extinction ratio of 14.17 dB and a corresponding energy loss of 50% are achieved directly from LP micro-LEDs under the injection current density of 200 A/cm2. The size-dependent effect of LP micro-LED is also investigated and it is found that smaller sized LP micro-LEDs have smaller extinction ratio due to sidewall light leakage. The reported GaN-based LP micro-LEDs have excellent potential to be utilized in 3D micro-LED displays.