Time-resolved cathodoluminescence assessment of deep-level transitions in hydride-vapor-phase-epitaxy GaN

Abstract

The temporal behavior of deep-level luminescence emissions in undoped hydride-vapor-phase-epitaxy GaN layers of different thicknesses has been investigated by time-resolved cathodoluminescence (TRCL). The complex nature of the yellow luminescence is revealed in the TRCL spectra by the presence of two bands peaked at 2.22 and 2.03 eV. A red band with a decay time of 700 mus, centered at about 1.85 eV, dominates spectra recorded for long delay times. Exponential transients with associated decay times of hundreds of mus were measured at 87 K for all the deep-level emissions found in the layers.