Cathodoluminescence wavelength imaging of mu m-scale energy variations in InAs/GaAs self-assembled quantum dots

Cathodoluminescence wavelength imaging of InAs/GaAs self-assembled quantum dots (SAQDs) was performed to study the spatial variation in the spectral l ine shape of the broadened quantum dot (QD) ensemble. The line shape was fo und to vary on a scale of similar to mu m, revealing attendant variations i n the size distribution of SAQD clusters on this spatial scale. Energy vari ations in clusters of SAQDs are found to exhibit a spatial correlation with the efficiency of luminescence and the activation energy for thermal re-em ission of carriers. A reduction in the energy variation of the QD clusters occurs when the thickness of the spacer layers in vertically self-organized samples is reduced or the number of stacks is increased. (C) 2000 American Institute of Physics. [S0003-6951(00)01823-4].