Spatially Resolved Visible Luminescence of Self-Assembled Semiconductor Quantum Dots

Ensembles of defect-free InAIAs islands of ultrasmall dimensions embedded in AIGaAs have been grown by molecular beam epitaxy. Cathodoluminescence was used to directly image the spatial distribution of the quantum dots by mapping their luminescence and to spectrally resolve very sharp peaks from small groups of dots, thus providing experimental verification for the discrete density of states in a zero-dimensional quantum structure. Visible luminescence is produced by different nominal compositions of InxAI(1-x)As-AIyGa(1-y)As.