Cathodoluminescence study of the Y-0 emission from ZnSe films

The Y-0 emission from an MBE grown sample of ZnSe/GaAs has been studied by TEM-CL technique. Thin films were prepared by removing the GaAs substrate by ion milling. Misfit dislocations were directly observed by TEM, and examined by monochromatic CL imaging. It was found that the Y-0 emission comes from threading dislocation parts, bent parts, and tie points of the misfit dislocations with Burgers vectors of 1/2 < 110 >. This suggests that the Y-0 emission originates from an electronic state formed at the localized structure of the misfit dislocations. However, some of the tie points are not luminescent, though they have the same character as that of the luminescent ones. Therefore we have to consider an additional factor to explain the behavior of the Y-0 emission, such as formation of a point defect state combined with dislocation core.