Electroluminescence from GaN-Based Quantum Dots

Bulk gallium nitride (GaN) has shown great success in light-emitting diodes (LEDs), but the use of its counterpart GaN quantum dots (QDs) to obtain electroluminescence has not yet been reported. In this work, the first GaN-based QLED is demonstrated using Zn-doped GaN (GaN: Zn) QDs, which is achieved through the combination of trap passivation, energy level adjustment, and morphology engineering. Pure GaN QDs and GaN: Zn QDs are synthesized, and it is found that Zn doping shifts the GaN QD emission from 321 to 377 nm and tunes the highest occupied molecular orbital energy level from 8.6 eV (of original GaN QDs) to 6.9 eV. Multiple washing posttreatment is further developed to improve QD film morphology and size distribution. The optimized GaN: Zn QDs are employed to fabricate solution-processed LEDs, and the first GaN-based QLEDs are reported with a maximum quantum efficiency of 0.004%.