Dislocation-Free InGaN Nanoscale Light-Emitting Diode Pixels on Single-Crystal GaN Substrates

Indium gallium nitride (InGaN) quantum well (QW) micro- and nanoscale light-emitting diodes (LEDs) are promising for next-generation ultrafast optical interconnects and augmented/virtual reality displays. However, scaling to nanoscale dimensions presents significant challenges including enhanced nonradiative surface recombination, defect and/or dislocation-related emission degradation, and nanoscale pixel contact formation. In this work, we demonstrate strain-engineered nanoscale blue LED pixels fabricated via top-down nanostructuring of an all-InGaN quantum well/barrier heterostructure grown by plasma-assisted molecular beam epitaxy (PAMBE) on significantly low dislocation-density single-crystal GaN substrates (in the order of ∼105–106 cm–2; 2 to 3 orders of magnitude lower than commercial GaN/Sapphire templates). Sidewall passivation using atomic layer deposition (ALD) of Al2O3 enables excellent diode behavior, including a rectification ratio >104 between −5 V and +5 V and extremely low reverse leakage (∼0.01 A/cm2 at −10 V). Monte Carlo analyses suggest almost 100% yield of completely dislocation-free active regions for ∼450 nm nanopixels. Electroluminescence measurements show bright blue emission with a peak external quantum efficiency (EQE) of 0.46% at ∼1.2 kA/cm2. Poisson–Schrödinger simulations reveal ∼20% strain relaxation in the QW, effectively mitigating the quantum-confined Stark effect (QCSE). Additionally, finite-difference time-domain (FDTD) simulations confirm that the nanoscale geometry enhances light extraction efficiency by over 40% compared to planar designs, independent of substrate materials. These results establish a scalable pathway for dislocation-free, high-brightness InGaN μLED arrays suitable for advanced display and photonic systems.