Optical properties of self-assembled InAs quantum dots grown on InAlAs/InP(001)

Self-organized InAs quantum islands (QIs) were grown in the Stranski-Krastanov regime, by solid source molecular beam epitaxy (SSMBE), on In 0.52 Al 0.48 As layer lattice matched to InP(001) substrate. The growth parameters are chosen to produce dot shaped InAs islands as indicated by the photoluminescence (PL) linear polarization which is about 9%. The PL spectrum reveals several resolvable components. PL versus power excitation and photoluminescence excitation (PLE) measurements show clearly that this multi-component spectrum is related to emission from transitions associated to fundamental and related excited states of quantum dots (QDs) having monolayer-height fluctuations. The integrated PL intensities have been measured as a function of temperature in the 8–300 K range. The PL intensity measured at 300K is only 8 times lower than at 8 K, indicating good carrier confinement in these InAs/InAlAs QDs. An enhancement of the PL intensity in the 8–90 K temperature range has been tentatively attributed to the exciton dissociation from the InAlAs barriers which then recombine radiatively in the InAs QDs.