The photoluminescence spectrum of small self-assembled In(Ga)As quantum dots grown on InP substrates was composed of distinct spectral lines. These lines correspond to monolayer variations in the dots smallest dimension: their heights. This phenomenon was used to study the diffusion of Ga atoms into the self-assembled quantum dots. It was demonstrated that substantial numbers of Ga atoms diffused from a strained GaInP layer, underneath the quantum dots, into the quantum dots.

Gallium Diffusion into Self-Assembled InAs Quantum Dots Grown on Indium Phosphide Substrates. T.Raz, N.Shuall, G.Bahir, D.Ritter, D.Gershoni, S.N.G.Chu: Applied Physics Letters, 2004, 85[16], 3578-80