Photo- and cathodoluminescence of ZnSSe quantum well heterostructures grown by MOVPE

Abstract Lateral- and depth-resolved cathodoluminescence as well as photoluminescence of MOVPE-grown single- and multi quantum well ZnSSe-based heterostructures in the temperature range of 14–300 K were investigated. The intensity ratios between different emission peaks and their dependencies on the electron penetration depth together with the temperature dependence of photoluminescence spectra permit concluding that the transport of non-equilibrium carriers or excitons in the structure is hindered by potential fluctuations created by microvariations of the sulphur content. The deep centres are localized mostly in the near-substrate region which is indicated by an increase of the self-activated emission at 2.2 eV with increasing electron beam penetration depth. Further improvement of layer homogeneity as well as a sufficient distance between the quantum well and the substrate together with minimization of the interlayer strain is necessary to improve the radiative properties of ZnSe-based heterostructures.