Cathodoluminescence of wide‐band‐gap II‐VI quaternary alloys

Abstract

Cathodoluminescence has been applied to study 1‐μm‐thick Zn1‐xMgxSySe1‐y alloys grown by molecular beam epitaxy. The observed cathodoluminescence spectra show the main band transition at 2.9 eV and a broad defect band around 2.2 eV. The analysis of the band intensities at different electron‐beam current densities shows different saturation behaviour of the defect band intensities for the samples. The saturation intensity and the luminescence lifetime correlate with the defect luminescence intensity and concentration. This is the reason of luminescence colour changes in dependence on the electron‐beam current density. These results were applied to comparative evaluation of the luminescent defect density. A respective cathodoluminescence imaging was used for observation of structural defects in the surface plane and at the ZnMgSSe‐layer/GaAs‐buffer interface. It enables an express non‐destructive analysis of defect density in the layers and heterostuctures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Estimation of relative defect densities in InGaN laser diodes by induced absorption of photoexcited carriers

“…Since the probability of a carrier to be trapped into defects will be proportional with the number of available empty defect states, the trapping dynamics will vary with the occupation of the defect states by electrons. Thus, an excitation-density dependent trapping dynamics is expected, which has a similar origin as observed in other defect-related phenomena showing saturation behaviors at high excitation intensities [19]. Figure 2 shows the dependence of the pump-probe signal on the pump intensity for the LD-A sample.…”