Optical characteristics of type？II hexagonal？shaped GaSb quantum dots on GaAs synthesized using nanowire self？growth mechanism from Ga metal droplet
- Optical characteristics of type？II hexagonal？shaped GaSb quantum dots on GaAs synthesized using nanowire self？growth mechanism from Ga metal droplet
- 송진동; Min Baik; Ji-hoon Kyhm; Hang-Kyu Kang; Kwang-Sik Jeong; Jong Su Kim; Mann-Ho Cho
- type-II; GaSb; Nanowire; droplet
- Issue Date
- Scientific Reports
- VOL 11, 7699
- We report the growth mechanism and optical characteristics of type-II band-aligned GaSb quantum dots (QDs) grown on GaAs using a droplet epitaxy-driven nanowire formation mechanism with molecular beam epitaxy. Using transmission electron microscopy and scanning electron microscopy images, we confrmed that the QDs, which comprised zinc-blende crystal structures with hexagonal shapes, were successfully grown through the formation of a nanowire from a Ga droplet, with reduced strain between GaAs and GaSb. Photoluminescence (PL) peaks of GaSb capped by a GaAs layer were observed at 1.11 eV, 1.26 eV, and 1.47 eV, assigned to the QDs, a wetting-like layer (WLL), and bulk GaAs, respectively, at the measurement temperature of 14 K and excitation laser power of 30 mW. The integrated PL intensity of the QDs was signifcantly stronger than that of the WLL, which indicated well-grown GaSb QDs on GaAs and the generation of an interlayer exciton, as shown in the power- and temperature-dependent PL spectra, respectively. In addition, time-resolved PL data showed that the GaSb QD and GaAs layers formed a self-aligned type-II band alignment; the temperature-dependent PL data exhibited a high equivalent internal quantum efciency of 15± 0.2%.
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