Shallow trap dynamics and non-thermal spectral shift in sub-10- <i>μ</i> m InGaN micro-LEDs

Abstract

Miniaturized InGaN micro-light-emitting diodes suffer reliability drifts that are not fully captured by conventional optical/electrical reporting. This study shows that, after 500-h direct current (DC) operation at 40 A cm−2, sub-10-μm devices exhibit a dominant-wavelength red-shift under fixed current that is non-thermal, as verified by &amp;lt;0.5 °C infrared thermography. A capacitance-decomposition model resolves the measured capacitance–voltage (C–V) dispersion into physically distinct trap ensembles and yields sub-40-ns response times, identifying shallow, sidewall-related traps as primary actors. The extracted trap dynamics quantitatively account for the increased series resistance, efficiency peak suppression, and weakened quantum-confined Stark effect screening responsible for the spectral shift. These results establish a mechanism-driven picture of reliability in miniaturized InGaN emitters and provide a general methodology for trap dynamics quantification in wide-bandgap optoelectronics. A display-driving implication is briefly noted, with details in the supplementary material.