Investigation on Green Micro-LEDs Based on Self-Assembled InGaN Quantum Dots Grown by Molecular Beam Epitaxy

Combining the advantages of low-dimensional and wide-gap semiconductors, InGaN quantum dots (QDs) are widely investigated as a candidate material for high-efficiency micro-LEDs. In this work, plasma-assisted molecular beam epitaxy (PAMBE) was used to grow self-assembled InGaN QDs for the fabrication of green micro-LEDs. The InGaN QDs have a rather high density of over 3.0×10 ¹⁰ cm ⁻² and show good dispersion and relatively uniform size distribution. A green LED with the size of 300 μm × 300 μm based on InGaN/GaN multi-quantum dots (MQDs) was fabricated. In addition, the preparation of micro-LEDs with different diameters (from 4 μm to 20 μm) and arrays of them with an emission wavelength of 537 nm have been finished. The luminescence tests show that InGaN QD-based micro-LEDs have excellent wavelength stability with the increase of injection current density, which is attributed to the shielding effect of QDs on the polarized field. This performance is of great significance for full-color micro-LED displays.