The annealing of InGaAs quantum dots that were fabricated by means of metal-organic chemical vapour deposition, and were covered with a very thin GaAs cap layer, completely eliminated large dislocated InGaAs clusters and markedly improved the optical properties. The elimination of defects permitted the stacking of quantum dots.

1.3μm Luminescence and Gain from Defect-Free InGaAs/GaAs Quantum Dots Grown by Metal-Organic Chemical Vapour Deposition N.N.Ledentsov, M.V.Maximov, D.Bimberg, T.Maka, C.M.Sotomayor Torres, I.V.Kochnev, I.L.Krestnikov, V.M.Lantratov, N.A.Cherkashin, Y.M.Musikhin, Z.I.Alferov: Semiconductor Science and Technology, 2000, 15[6], 604-7