Direct optical observations were made of diffusion-related deep levels that were associated with interdiffusion in superlattice structures. Low-energy cathodoluminescence spectroscopy was used to investigate the formation and evolution of deep levels under various conditions. It was found that the spatial distribution of the deep levels was strongly related to the extent of superlattice intermixing, as measured using secondary ion mass spectrometry and photoluminescence spectroscopy. The results strongly suggested that a larger interdiffusion rate of the Si-induced layer intermixing was related to the formation of a deep level which was associated with an optical emission at 1.3eV.

R.E.Viturro, B.L.Olmsted, S.N.Houde-Walter, G.W.Wicks: Journal of Vacuum Science and Technology B, 1991, 9[4], 2244-50