Effect of Growth Interruption in Migration Enhanced Epitaxy on InAs/GaAs Quantum Dots

概要

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In this study, we investigated the effect of growth interruption time ($t_{\text{GI}}$) during migration enhanced epitaxy (MEE) growth of self-assembled InAs/GaAs quantum dots (QDs) to control the density of the QDs without any substrate rotation stop during QD formation. By manipulating the growth factor ($t_{\text{GI}}$), the control of QD density in the range of $3.4 \times 10^{9}$–$3.5 \times 10^{10}$ dots/cm2, as well as the QD shape, was demonstrated. We concluded that three phenomena occur during growth interruption: 1) In re-evaporation, 2) In segregation, and 3) the redistribution of InAs QDs. From photoluminescence (PL), it is found that the emission wavelength of samples increased from 967.7 to 1151.7 nm as $t_{\text{GI}}$ increased due to redistribution. In addition, we confirmed PL peak emissions from QDs, quasi-three-dimensional (Q3D) clusters, and wetting layer. As a result, the manipulation of $t_{\text{GI}}$ in the MEE method can control the density, uniformity, size, and wavelength of QDs.
2009-09-25