Families of islands in InAs/InP self-assembled quantum dots: a census obtained from magneto-photoluminescence

Abstract

The low temperature photoluminescence properties of InAs/InP self-assembled quantum dots are investigated in magnetic fields up to 17 T. The zero field spectrum exhibits a number of inhomogeneously broadened peaks similar to the highly excited spectrum of InAs/GaAs quantum dots in which emission from excited states can be observed. However, for InAs/InP dots, application of a magnetic field in the Faraday configuration reveals only weak diamagnetic shifts, thus proving that the transitions originate from zero angular momentum states consistent with ground state emission from distinct families of islands present in the sample. The diamagnetic shift is observed to increase as the thickness of the island family increases. Calculations performed assuming a flat disc geometry show that the latter effect can be accounted for by the change in carrier effective mass as the dot thickness increases.

Growth of InAs/InP-based quantum dots for 1.55 μm laser applications

“…2 shows the PL for samples A-D. A clear trend is observed, a decrease in growth rate results in a red shift in PL peak position. In this materials system the dot height is significantly smaller than the lateral dimensions, so the ground state energy is dominated by the dot height [19]. This means that as the growth rate decreases the average dot height must be increasing.…”

Carrier thermal escape in families of InAs/InP self-assembled quantum dots

“…In order to solve some of the problems mentioned above, we present a study of the thermal quenching from two samples that contain a single layer of InAs QDs embedded in an InP matrix. Their PL spectra show several well-resolved emission bands, extending from 0.75 to 1.1 eV, that can be associated with families of QDs that differ in height by 1 ML, [21][22][23][24][25][26][27][28] while their PL excitation ͑PLE͒ spectra reveal absorption edges that we associate with QD excited states and WL resonances. The evolution with temperature of the multimodal PL of our samples imposes stringent constraints on a model based on coupled rate equations as it should reproduce the thermal behavior of many peaks with the same set of parameters.…”

Vacancy-mediated intermixing in InAs/InP(001) quantum dots subjected to ion implantation

“…These peaks correspond to the fundamental electronϪheavy-hole transitions ͑e1-hh1͒ of ensembles, or families, of QDs each having the same thickness ͑h QD ͒ in terms of an integer number of monolayers. 27,28 The lowintensity peak observed at 1160 meV in Fig. 2͑a͒ can be attributed to the emission from the wetting layer ͑WL͒.…”

“…As a starting point, the initial peak positions for the as-grown samples were estimated based on a previous work. 28 The full widths at half maximum ͑FWHM͒ of the peaks-which are related to inhomogeneous broadening within a given family due to small variations in lateral size, composition, electronic environment, or from roughness in the thickness 27 -were constrained to increase with emission energy since interfacial roughness is expected to cause larger relative changes in the confinement emission energy in thinner QDs. 31 The results of this fitting procedure are illustrated in Figs.…”