On the origin of the blueshift from type-II quantum dots emission using microphotoluminescence

Abstract

Effects of thermal annealing on the emission properties of type-II InAs/GaAsSb quantum dots Appl. Phys. Lett. 94, 053101 (2009); 10.1063/1.3062979Photoluminescence studies of type-II self-assembled In 0.55 Al 0.45 As/Al 0.5 Ga 0.5 As quantum dots grown on (311)A GaAs substrate

Carrier dynamics in stacked InP∕GaAs quantum dots

“…Our results could actually be more straightforwardly explained if the InP / GaAs system had a type-I interface. This hypothesis is, however, in disagreement with the large blueshift of the photoluminescence peak from a QD structure versus the excitation intensity, 12,13 which is a typical property of type-II systems. We discuss alternative explanations for our results considering a type-II alignment.…”

“…4,5 Structures composed of stacked QDs with type-I interface band alignment have been intensively investigated but few works have been reported for type-II systems, such as Ge/ Si, 6,7 GaSb/ GaAs, [8][9][10] and InP / GaAs. [11][12][13] In these structures, only one type of carrier is confined in the QD whereas the other carrier remains in the barrier layer surrounding the dot. The Coulomb attraction and the overlap of the carriers' wavefunctions are thus significantly reduced for type-II systems.…”

Controlling alloy composition of InAsP self-assembled quantum dots embedded in GaAs

“…8 In addition to these possibilities, we have also to consider that the system InAsP in GaAs will undergo a type I to type II band line up, 9 which may allow some control of recombination time. Finally, the ability of controlling the mixing in the anion sublattice of strained layers is of fundamental importance as well, and SK islands are an interesting prototypical system, as the amount of strain can be substantial.…”

Optical properties of type-I and II quantum dots

“…In this system electrons are confined in the InP dots and holes are localized at the GaAs layer around the dots. The optical properties of type-II QDs, such as GaSb/GaAs [4][5][6][7], Ge/Si [8] and recently InP/GaAs [3,9], are less investigated compared to type-I systems. The spatial separation of electrons and holes at distinct material layers leads to a spatial indirect recombination resulting in relatively longer radiation lifetimes, as compared to type-I systems, which is a very attractive characteristic for device applications such as optical memories [10].…”

“…In this scenery the magnitude of the electron-hole Coulomb interaction is strongly dependent on the spatial charge distribution. Here we present a review of optical studies in two systems with interfaces type-I [2] and II [3] that explore the particularities of the band alignment on the QD optical properties.…”