Carrier relaxation mechanisms in self-assembled (In,Ga)As/GaAs quantum dots: Efficient P -> S Auger relaxation of electrons

摘要

We calculate the P-shell--to-S-shell decay lifetime \tau(P->S) of electronsin lens-shaped self-assembled (In,Ga)As/GaAs dots due to Auger electron-holescattering within an atomistic pseudopotential-based approach. We find thatthis relaxation mechanism leads to fast decay of \tau(P->S)~1-7 ps for dots ofdifferent sizes. Our calculated Auger-type P-shell--to-S-shell decay lifetimes\tau(P->S) compare well to data in (In,Ga)As/GaAs dots, showing that as long asholes are present there is no need for an alternative polaron mechanism.