Dynamics of Excitation Transfer Inside InAs/GaAs Quantum Dot System

We present time-resolved photoluminescence investigations of InAs/GaAs structures containing quantum dots with the ground state at 1.43 eV. State filling effect and a Pauli blocking effect were clearly observed. These effects significantly influenced dynamics of excitation transfer from upper to lower state inside a dot leading to non-exponential dynamics. Numerical model based on nonlinear rate equations was proposed. The model described well the experimental data providing values of: lifetime of the ground state 0.53±0.03 ns, lifetime of excited state (when the ground state is full) 1.1±0.2 ns, and internal relaxation time (when the ground state is empty) 0.07±0.01 ns.