Size-dependent excitongfactor in self-assembled InAs/InP quantum dots

Abstract

We have studied the size dependence of the exciton g-factor in self-assembled InAs/InP quantum dots. Photoluminescence measurements on a large ensemble of these dots indicate a multimodal height distribution. Cross-sectional Scanning Tunneling Microscopy measurements have been performed and support the interpretation of the macro photoluminescence spectra. More than 160 individual quantum dots have systematically been investigated by analyzing single dot magnetoluminescence between 1200 nm and 1600 nm. We demonstrate a strong dependence of the exciton g-factor on the height and diameter of the quantum dots, which eventually gives rise to a sign change of the g-factor. The observed correlation between exciton g-factor and the size of the dots is in good agreement with calculations. Moreover, we find a size dependent anisotropy splitting of the exciton emission in zero magnetic field.

gfactors and diamagnetic coefficients of electrons, holes, and excitons in InAs/InP quantum dots

“…1), as was inferred from cross-sectional scanning tunneling microscopy in Ref. 27. Calculations for various heights h and radii r for the quantum dots have been performed to study the size dependence of the g factor and diamagnetic coefficient.…”

“…The black squares are the experimental data points from Ref. 27. We will first discuss the g ex factor.…”

“…It was experimentally established 27 that the general trend of the g ex factor with emission energy originates from the dependence on the height of the QDs. This is confirmed by the theoretical calculation, in which irrespective of the exact radius of the QDs the height dependence matches with the experimentally observed trend.…”

“…26. Recent experimental work 27 has investigated the magneto-optical properties of such dots by probing the component of the exciton g tensor along the [001] direction (this component is from now on referred as the g factor). A strong dependence of the exciton g factor (g ex ) on the dot height was shown, whereas the same work found the exciton diamagnetic coefficient (α ex ) was mostly independent of the height.…”

Exciton spin relaxation in InAs/InGaAlAs/InP(001) quantum dashes emitting near 1.55μm

“…Existing reports address only the problem of either exciton or electron/hole g-factors in InAs/InP QDs. [10][11][12][13] However, issues such as the longitudinal or transverse spin relaxation or the role of spin pumping schemes on the spin memory effect in this particular quantum system have not been explored up to date.In this letter, we investigate properties of polarized emission and spin states of excitons confined in an ensemble of InAs/In 0.53 Ga 0.23 Al 0.24 As/InP(001) QDashes by means of polarization-and time-resolved photoluminescence (TRPL), as well as photoluminescence excitation spectroscopy (PLE). We demonstrate various schemes of spin injection and their impact on the spin memory effect in QDashes emitting near 1.55 lm.…”