A multi-layer structure which consisted of 20 layers of self-assembled quantum dots was grown by means of molecular-beam epitaxy and was studied by using transmission electron microscopy. Threading dislocations were observed which originated from large strain-relaxed incoherent islands in a quantum-dot layer. The dislocations were of 30º type, lay in [1¯12] and [¯112] directions, and were generated by misfit between large InAs islands and a GaAs overlayer.

Threading dislocations in the multilayer structure of InAs self-assembled quantum dots K.Shiramine, Y.Horisaki, D.Suzuki, S.Itoh, Y.Ebiko, S.Muto, Y.Nakata, N.Yokoyama: Japanese Journal of Applied Physics - 1, 1998, 37[10], 5493-6