Temperature dependence of electron redistribution in modulation-doped InAs/GaAs quantum dots

In this work we report the photoluminescence (PL) and interband absorption study of Si-modulation-doped multilayer InAs/GaAs quantum dots grown by mol ecular beam epitaxy (MBE) on (100) oriented GaAs substrates. Low-temperatur e PL shows a distinctive double-peak feature. Power-dependent PL and transm ission electron microscopy (TEM) confirm that they stem from the ground sta tes emission of islands of bimodal size distribution. Temperature-dependent PL study indicates that the family of small dots is ensemble effect domina ted while the family of large dots is likely to be dominated by the intrins ic property of single quantum dots (QDs). The temperature-dependent PL and interband absorption measurements are discussed in terms of thermalized red istribution of the carriers among groups of QDs of different sizes in the e nsemble. (C) 2000 Elsevier Science B.V. All rights reserved.