Microscopic information on the optical properties of Se(g)-type dislocations, in ZnSe layers grown onto (001)GaAs substrates by means of molecular beam epitaxy, were obtained by using micro-cathodoluminescence and photoluminescence techniques. The Se(g)-type misfit dislocations were found to nucleate firstly within high-quality pseudomorphic films above the critical thickness. The individual Se(g) misfit segments were the only local emission centres of a so-called Y luminescence. The latter was strongly polarized in the defect-line direction, and exhibited a pronounced spectrum fine-structure which was related to the particular structural configuration; as determined by the dissociation of perfect 60° dislocation segments into pairs of 30°/90° Shockley partials which bordered a stacking-fault ribbon. By studying the dislocation-induced Y luminescence, with respect to polarization properties and its correlation with the defect structure, results were found which supported the idea that the dislocation-induced luminescence could be attributed to 1-dimensional excitonic states at the line defect. The local strain-field which was thought to be the origin of defect-bound electronic states could be examined at isolated Se(g) dislocations by analysing the microscopic dependence of the observed polarization of the free exciton emission in the layer matrix. The polarization properties of free exciton emission resulted from an anisotropic relief of layer strain by the Se(g) misfit segment arrangement.

Optical Characterization of Isolated Se(g)-Type Misfit Dislocations and their Influence on Strain Relief in Thin ZnSe Films. U.Hilpert, J.Schreiber, L.Worschech, L.Höring, M.Ramsteiner, W.Ossau, G.Landwehr: Journal of Physics - Condensed Matter, 2000, 12[49], 10169-74