Modelling of electronic states in InAs/GaAs quantum dots with GaAsSb strain reducing overlayer
|Článek v odborném periodiku
|Časopis / Zdroj
|Journal of Physics: Conference Series
|Fakulta / Pracoviště MU
|Fyzika pevných látek a magnetismus
|Quantum Dots; Semiconductor Compounds; Mechanical properties of nanoscale systems
|We present results of our 8-band k.p calculations of the emission energy of InAs/GaAs quantum dots (QDs) covered with GaAs1-xSbx strain reducing overlayer (SRO). In agreement with previous experimental observations we find a strong red shift of the emission with increasing Sb content. We explain this effect by: (1) The lowering of the valence band offset between the QD and the SRO with increasing Sb content resulting in the type-II QDs with holes confined in the SRO for Sb concentration above 14%. (2) The reduction of compressive strain inside the QDs. The contributions of these mechanisms to the total red shift are estimated and compared. For realistic shape and size of the QD and a realistic value of the SRO thickness the previously measured photoluminescence data are reproduced with fairly good accuracy.