The influence of structural defects in ZnSe/GaAs heterostructures on luminescence properties

Cathodoluminescence (CL) measurements were carried out on ZnSe/GaAs heterostructures grown by metal-organic vapour-phase epitaxy, partly with different pre-growth treatments. The influence of structural defects on the luminescence properties of ZnSe epilayers both above and below the experimentally obtained value of the critical thickness for strain relaxation were studied. The CL results combined with scanning transmission electron microscopy demonstrate that there is a correlation between structural defects and the deep-level emission at around 580 nm named the SA emission. In addition, a strong influence of the pre-growth treatment on the crystalline quality of epilayers of ZnSe was observed.