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Long-wavelength photoluminescence from stacked layers of high-quality type-II GaSb/GaAs quantum rings
Research output: Contribution to journal › Journal article
Published
| Journal publication date | 17/01/2013 |
|---|---|
| Journal | Crystal Growth and Design |
| Journal number | 3 |
| Volume | 13 |
| Number of pages | 5 |
| Pages | 1226-1230 |
| Original language | English |
Abstract
We report the successful molecular-beam epitaxial growth of 10 stacked layers of GaSb/GaAs quantum rings using a new procedure. Exact control of the arsenic flux during capping helps to reduce the strong group-V As–Sb exchange reactions, enabling the rings to be capped at the same growth temperature (480 °C) without dissolution. X-ray diffraction and transmission electron microscopy indicate excellent structural quality and uniformity with no threading dislocations. This is due to the reduction in the average strain through the quantum-ring formation. The total ring density in the stacks is 1 × 1011 cm–2. An unusually long-wavelength quantum-ring photoluminescence peak of 1.3 μm is observed at low temperature, which is attributed to a reduction in the quantum-ring charging due to lower unintentional p-doping in the GaAs cap layer. The impact that this effect will have on future device designs in solar cells and lasers is also discussed.