Cathodoluminescence image of defects and luminescence centers in ZnS/GaAs(100)

Abstract

The spatial distributions of the cathodoluminescence (CL) emissions from thin ZnS films on GaAs(100) have been examined by the low-temperature CL measurement system combined with a transmission electron microscope (TEM). The correlation between these CL emissions and structural defects were studied by comparing the monochromatic CL images with the TEM images for both plan-view and cross-sectional observations. It is found that the neutral acceptor–bound exciton associated emission (A0,X) and the free-electron-to-ionized acceptor transition emission (e,A) are affected by the stacking fault distribution. The localization of the emission due to the deep-level emission transition near the interface suggest the diffusion of Ga atoms from the GaAs substrate. The characteristic distributions of the CL emission regions can be explained by considering the competitions among the recombination channels of those radiative processes for each type of an excess carrier, an electron, or a hole.