Wafer-Scale Semipolar Micro-Pyramid Lighting-Emitting Diode Array

Abstract

InGaN-based micro-structured light-emitting diodes (µLEDs) play a critical role in the field of full-color display. In this work, selected area growth (SAG) of a micro-pyramid LED array was performed on a 2-inch wafer-scale patterned SiO2 template (periodicity: 4 µm diameter), by which a uniform periodic µLED array was achieved. The single-element pyramid-shaped LED exhibited 6 equivalent semipolar {1-101} planes and a size of about 5 µm, revealing a good crystalline quality with screw and edge dislocation densities of 8.27 × 107 and 4.49 × 108 cm−2. Due to the stress–relaxation out of the SAG, the as-built compressive strain was reduced to 0.59 GPa. The µLED array demonstrated a stable emission, confirmed by a small variation of electroluminescence (EL) peak wavelength over a wide range of current density up to 44.89 A/cm2, as well as tiny fluctuations (within 1.9 nm) in the EL full width at half maximum. The photoluminescence peak wavelength exhibits a good uniformity throughout the whole wafer with a discrete probability of only 0.25%.