Impurity-free disordering of InAs/ InP quantum dots
نویسندگان
چکیده
Impurity-free disordering IFD of the InAs quantum dots QDs capped with either an InP layer or an InGaAs/ InP bilayer is studied. The samples are coated with a SiO2 or TiO2 dielectric layer followed by rapid thermal annealing at 700, 750, 800, and 850 °C for 30 s. A large differential energy shift of 157 meV is induced by SiO2 in the QDs capped with an InGaAs/ InP bilayer. Contrary to the reported results on the suppression of intermixing of GaAs based QDs by TiO2, the authors find that intermixing of InAs/ InP QDs is promoted by TiO2. X-ray photoelectron spectroscopy depth profiles show that both In and P outdiffuse to a TiO2 layer whereas Ga, In, and P outdiffuse to a SiO2 layer leading to different degrees of intermixing. The results indicate that a group V interstitial diffusion mechanism might be responsible for IFD of InAs/ InP QDs. © 2007 American Institute of Physics. DOI: 10.1063/1.2748845
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