Tuning of the electronic properties of self-assembled InAs/InP(001) quantum dots by rapid thermal annealing

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Abstract
We have investigated the effect of post-growth rapid thermal annealing on the low-temperature photoluminescence (PL) spectra of self-assembled InAs quantum dots(QDs)grown in InP(001) by chemical-beam epitaxy using both conventional and modified capping procedures. As-grown samples are characterized by a broad emission peak centered near 800–900 meV corresponding to distinct QD families of different sizes with no observable wetting-layer emission. Rapid thermal anneals were performed at 650 to 800 °C for 210 s, resulting in blueshifts of up to 120 meV due to intermixing. While the PL emission energies of the various QD families shift at similar rates upon annealing, the peak widths remain approximately constant. Finally, we show that the growth of a low-temperature InP cap layer containing a large number of point defects significantly enhances interdiffusion and results in PL blueshifts in excess of 300 meV.