Degradation defects which were introduced by the electron-beam bombardment of graded-index separate-confinement blue-green laser structures were studied by means of transmission electron microscopy. It was found that most defects appeared as tree-like arrangements of small extrinsic and intrinsic dislocation loops in ±[100] or ±[010] directions, and were located within the quantum well or at its boundaries. The Burgers vectors of the loops were identified as being ½[01¯1] and ½[10¯1] for loops in the ±[100] and ±[010] directions, respectively.

J.M.Bonard, J.D.Ganière, L.Vanzetti, J.J.Paggel, L.Sorba, A.Franciosi, D.Hervé, E.Molva: Philosophical Magazine Letters, 1997, 76[3], 181-7