Electrical and optical analysis of core–shell InGaN/GaN nanowire array μLEDs by analytical compact modeling

Abstract

We extend an analytical electrical compact model, originally developed for planar InGaN/GaN quantum-well (QW) micro-light-emitting diodes (μLEDs), to core–shell InGaN/GaN QW nanowire-array μLEDs. By exploiting the near invariance of the measured current density–voltage (J–V) characteristics with respect to the number of nanowires, the array can be represented by an equivalent single-nanowire model, enabling extraction of average electrical parameters, including the effective hole diffusion coefficient, as well as the series and thermal resistances. The model enables determination of the hole density injected into the QW and direct extraction of the radiative recombination coefficient B from the dependence of optical power on hole density without requiring specialized measurements. Incorporation of the measured light extraction efficiency and the hole density into the ABC framework allows prediction of the external quantum efficiency (EQE) as a function of both current density and hole concentration. A hole concentration-dependent Auger coefficient is introduced to account for phase-space filling effects at high injection levels, reproducing the observed EQE asymmetry not described by the conventional ABC model. The extracted radiative recombination coefficient further enables evaluation of the modulation bandwidth, which is relevant for visible-light communication applications.