Work

Model-constrained nanoscale 3D cathodoluminescence reconstruction of InGaN LEDs via coupled electron–photon transport

Year: 2026

Type: article

Abstract: Depth-resolved cathodoluminescence (DRCL) is widely used to probe semiconductor heterostructures, but voltage-dependent spectra are depth-convolved by the finite electron-matter interaction volume and photon transport across multilayer interfaces. Here we develop a model-constrained nanoscale three-dimensional (3D) CL reconstruction framework for InGaN LEDs based on multi-voltage scanning electron microscope (SEM) CL measurements and Monte Carlo electron-photon transport. The model couples stochastic primary-electron penetration and energy deposition with wavelength-dependent refraction, reflection, transmission, absorption, and reabsorption-induced secondary excitation in the multiple-quantum-well (MQW) region. Emission events are retained with their depth, layer, wavelength, and propagation histories and accumulated into nanometer-scale bins to reconstruct luminescence distributions. Multi-voltage top-view CL measurements from 4 to 10 kV, side-view CL spectra from focused-ion-beam (FIB) prepared lamellae, and transmission electron microscopy structural references were used to constrain and evaluate the model. The simulated spectra agree with the measured spectra, and the reconstructed 3D luminescence volume resolves V-pit-related emission heterogeneity, the MQW-related active-region luminescence distribution, and the transition to the prestrained-well-related emission component centered near 390 nm. After calibration with cross-sectional CL and TEM references, this framework reduces ambiguity from electron-interaction-volume broadening and interlayer photon transport, providing a practical top-view route for depth-localized optical analysis of comparable InGaN epitaxial nanostructures.

Source: Optics Express

DOI: 10.1364/oe.614482