Inter-dot coupling and excitation transfer mechanisms of telecommunication band InAs quantum dots at elevated temperatures

Abstract

We investigate the photoluminescence temperature dependence of individual InAs/InGaAlAs quantum dots emitting in the optical telecommunication bands. The high-density dots are grown on InP substrates and the selection of a smaller dot number is done by the processing of suitable nanometer-sized mesas. Using ensembles of only a few dots inside such mesas, their temperature stability, inter-dot charge transfer, as well as carrier capture and escape mechanisms out of the dots are investigated systematically. This includes the discussion of the dot ensemble and individual dots. Among the single-dot properties, we investigate the transition of emission lines from zero-phonon line to acoustic phonon sideband-dominated line shape with temperature. Moreover, the presence of single recombination lines up to temperatures of about 150 K is demonstrated.

Carrier dynamics and photoluminescence quenching mechanism of strained InGaSb/AlGaSb quantum wells

“…The nature of the carrier escape mechanism has been discussed with the ratio of [41][42][43][44] v ¼ E a =DE;…”

“…In the case of correlated electron-hole (e-h) escape, ¼ 1 = 2 is satisfied. 42 In the case of InAs/InGaAlAs 44 and InAs/InP 41 emitting in the 1.55-lm band, the authors concluded ¼ 1 = 2 , that is, the mechanism behind the thermal escape was suggested to be a correlated e-h pair escape. In our present InGaSb/AlGaSb, QW sample also emitting in the 1.55-lm band, ¼ 0.12 is obtained and thereby the single carrier (hole) escape mechanism dominates.…”

Spectral and Transient Luminescence Measurements on GaSb/AlGaSb Quantum Wells Grown on GaSb/GaAs Heterojunctions with and without Interfacial Misfit Arrays

“…When ν = ½, the carrier escape is in the form of correlated electron-hole pairs and this mechanism was observed with GaInP/AlGaInP QW, 35) InAs/GaAs QD, 36) InAs/InP QD, 37) and InAs/InGaAlAs QD. 38) This mechanism is probable when the band discontinuities both in the conduction and valence bands have relatively large values for carrier confinements. When ν < ½, single carrier escape mechanism dominates 36) and this is applied in the present GaSb/AlGaSb case.…”

Time-resolved measurements of Cooper-pair radiative recombination in InAs quantum dots

“…With the higher excitation, population of the lowest energy states of larger dots are saturated, and the population of their excited states and carrier transfer to smaller QDs with higher QD-state energies take place through coupled excited states. 29 Then, when the conduction-band QD-state energies of dominantly luminescent QDs come to near resonance with the SC-DOS, the SC recombination rate reaches the maximum as shown in Fig. 7.…”