Individual quantum dots were produced by selective interdiffusion between the barriers and the quantum well layer in a CdTe/CdMgTe heterostructure. The heterostructure, with a SiO2 mask preliminarily deposited onto the surface, was subjected to short-term annealing for (410C, 60s). The mask contained open apertures with diameter up to 140nm. The annealing induces diffusion of Mg atoms into the depth of the quantum well. Diffusion was substantially enhanced under the mask. The induced lateral potential, with minimums in the regions of apertures of the mask, stimulates efficient localization of charge carriers that form quasi-zero-dimensional excitons. The study of radiative recombination suggested complete spatial confinement of the excitons. The confinement manifests itself in the observation of a substantially narrowed line of excitonic transitions, as well as in the observation of bi-excitons and excited states at high levels of photo-excitation. The characteristic energies of interlevel splitting and the bi-exciton binding energy showed that charge carriers were under the condition of weak confinement in the quantum dots.

Production of Quantum Dots by Selective Interdiffusion in CdTe/CdMgTe Quantum Wells. S.V.Zaitsev, M.K.Welsch, A.Forchel, G.Bacher: Semiconductors, 2007, 41[11], 1339-44