Enhancing optical output power efficiency in nitride-based green micro light-emitting diodes by sidewall ion implantation

Though micro-LED (light-emitting diode) displays are considered the emerging display technology, the micron-scale LED chip size encounters severe efficiency degradation that may impact the power budget of the displays. This work proposes an ion implantation method to deliberately create a high-resistivity sidewall in the InGaN/GaN green LED. Our study demonstrates that ion implantation suppresses reverse leakage current due to the mitigation of sidewall defects. For an LED mesa size of 10 x 10 mu m2, optical output power density is improved by 36.2% compared to the device without implantation. Compared to a larger 100 x 100 mu m2 device without implantation, we achieve only 21.3% degradation of output power density under 10 A/cm2 injection for a 10 x 10 mu m2 LED with implantation. In addition, the ion implantation method can lower the wavelength shift by reducing light emission from the region near the sidewall (where the amount of Indium [In] clustering differs from the mesa region). The results show promise in addressing the efficiency challenges of micro-LED displays by selective ion implantation. An ion implantation method creates a high-resistivity sidewall in the InGaN/GaN green LED. Fewer injection carriers flow across mesa sidewalls that contain many dry etching-induced defects, thus mitigating non-radiative recombination. Light output can be significantly enhanced for micro-LEDs. image