The distribution of dislocations and domains found in thin ZnSe films grown by molecular-beam epitaxy on GaAs(100) has been examined with low-temperature cathodoluminescence (CL) imaging and spectroscopy. Dark-line and bright-line defects in the low-temperature CL imaging of the free-exciton (FE) and Y-band emissions, respectively, are found to correlate with the presence of [11̄0]-oriented misfit dislocations for 1-μm-thick films found to grow nearly two dimensionally. For a sample exhibiting mixed two- and three-dimensional growth characters, large domains (∼1-5 μm widths) in the CL imaging of the ZnSe FE emission were found to correlate with a cellular pattern found in the imaging of the GaAs exciton and band-edge-to-acceptor emissions. These results show that the optical properties of the ZnSe film and GaAs substrate are coupled and influenced by Zn diffusion into the substrate during growth.
ASJC Scopus subject areas
- Physics and Astronomy (all)