| Autor: |
Dion, C., Desjardins, P., Shtinkov, N., Schiettekatte, F., Poole, P. J., Raymond, S. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; Apr2008, Vol. 103 Issue 8, p083526-10, 10p, 10 Graphs |
| Abstrakt: |
This work investigates the interdiffusion dynamics in self-assembled InAs/InP(001) quantum dots (QDs) subjected to rapid thermal annealing in the 600–775 °C temperature range. We compare two QD samples capped with InP grown at either optimal or reduced temperature to induce grown-in defects. Atomic interdiffusion is assessed by using photoluminescence measurements in conjunction with tight-binding calculations. By assuming Fickian diffusion, the interdiffusion lengths LI are determined as a function of annealing conditions from the comparison of the measured optical transition energies with those calculated for InP/InAs1-xPx/InP quantum wells with graded interfaces. LI values are then analyzed using a one-dimensional interdiffusion model that accounts for both the transport of nonequilibrium concentrations of P interstitials from the InP capping layer to the InAs active region and the P–As substitution in the QD vicinity. It is demonstrated that each process is characterized by a diffusion coefficient D(i) given by D(i)=D0(i) exp(-Ea(i)/kBTa). The activation energy and pre-exponential factor for P interstitial diffusion in the InP matrix are Ea(P–InP)=2.7±0.3 eV and D0(P–InP)=103.6±0.9 cm2 s-1, which are independent of the InP growth conditions. For the P–As substitution process, Ea(P–As)=2.3±0.2 eV and (co/no)D0(P–As)∼10-5-10-4 cm2 s-1, which depend on the QD height and concentration of grown-in defects (co/no). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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