Diffusion process of excitons in the wetting layer and their trapping by quantum dots in sparsely spaced InAs quantum dot systems

Abstract

Photoluminescence of self-assembled InAs/GaAs quantum dots excited by ultraintensive femtosecond laser Wetting layer states of In As ∕ Ga As self-assembled quantum dot structures: Effect of intermixing and capping layer

Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots

“…The WL optical emission is pronounced and dominates over the QD optical emission. 20 This is the case of sample I, as it is shown in Figure 1. Fig.…”

“…In these circumstances, QD emission is stronger than WL emission. 20 This is the case of sample II, as it is shown in Figure 1.…”

“…In the literature, the problem has been divided into two extreme cases 18,20 : high and low QD density samples. In the first case, carrier trapping from WL to QDs is limited by QD to QD distance (d QDÀQD ).…”

“…2,6 These models reveal new effects like the competition between band narrowing by thermal escape processes and band broadening due to exciton-phonon interactions, 7,16 or the role of the wetting layer (WL) continuous states as a mediator for carrier diffusion. 4,6,8,9,11,[17][18][19][20] The thermally activated escape mechanism initiates the temperature dynamics and therefore has deserved a lot of attention in the past. It has been investigated attending to the available final states, i.e., QD excited states, 15,21 wetting layer, 4,6,7,13,20,22 GaAs barrier, 8,9,23 and impurity/defect levels.…”

“…4,6,8,9,11,[17][18][19][20] The thermally activated escape mechanism initiates the temperature dynamics and therefore has deserved a lot of attention in the past. It has been investigated attending to the available final states, i.e., QD excited states, 15,21 wetting layer, 4,6,7,13,20,22 GaAs barrier, 8,9,23 and impurity/defect levels. [23][24][25][26] Thermal escape can be also investigated attending to the nature of the particles being promoted to a higher energy state.…”