Cathodoluminescence wavelength imaging of mm-scale energy variations in InAsÕGaAs 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 line shape of the broadened quantum dot ~QD! ensemble. The line shape was found to vary on a scale of ;mm, revealing attendant variations in the size distribution of SAQD clusters on this spatial scale. Energy variations in clusters of SAQDs are found to exhibit a spatial correlation with the efficiency of luminescence and the activation energy for thermal re-emission 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. © 2000 American Institute of Physics. @S0003-6951~00!01823-4#