InxGa1-xAs/GaAs interfaces: From 2D islands to quantum dots

In this paper we try to give a unified picture of InxGa1-xAs/GaAs quantum systems (0 less than or equal to x less than or equal to 1), as deduced primarily by optical measurements at 10 K. This has been made possible by the systematic investigation of photoluminescence and photoluminescence excitation of InGaAs/GaAs strained heterostructures differring for indium molar fraction and well width. The large number of samples used has allowed us to change in a controlled way the degree and source of disorder in the samples. The evolution from a two-dimensional growth, with formation of InGaAs and GaAs interconnected two-dimensional islands at the interfaces, to a three-dimensional growth, with self-aggregation of InGaAs dots, has been monitored, also with the help of structural measurements.