InGaN Nanopixel Arrays on Single Crystal GaN Substrate

TL;DR

This paper presents the fabrication and characterization of high-efficiency, nanoscale InGaN micro-LED arrays on low-dislocation GaN substrates, demonstrating promising applications in advanced display technologies.

Contribution

It introduces a scalable top-down nanostructuring method for dislocation-free InGaN micro-LEDs with enhanced light extraction and reduced QCSE, advancing display and photonic system integration.

Findings

Achieved bright blue emission with 0.46% EQE.

Demonstrated over 40% light extraction enhancement.

Monte Carlo analysis predicts near 100% yield of defect-free pixels.

Abstract

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. Sidewall passivation using atomic layer deposition (ALD) of Al2O3 enables excellent diode behavior, including a high rectification ratio and extremely low reverse leakage. 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%. Poisson Schrodinger simulations reveal partial 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 microLED arrays suitable for advanced display and photonic systems.