Highly uniform, multi-stacked InGaAs/GaAs quantum dots embedded in
a GaAs nanowire
Supplemental material
J. Tatebayashia1, Y. Ota1, S. Ishida1,2, M. Nishioka1,2, S. Iwamoto1,2 and Y. Arakawa1,2
1
NanoQUINE, the University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo, 153-8505,
JAPAN
2
Institute of Industrial Science, the University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo,
153-8505, JAPAN
1. -PL characteristics at 6K of 5-stack In0.22Ga0.78As/GaAs NWQDs before and after
tuning/counter-tuning the growth durations
We perform another optical characterization to clarify whether we are able to control the broadness
of the PL from multi-stacked QDs in a single GaAs NW. Figure S1 shows the -PL spectra at 6K of 5stack NWQDs with a 200-nm GaAs spacer before and after tuning (counter-tuning) the growth duration.
If the growth duration of all QDs are identical, the emission spectrum exhibits 5 separate sharp peaks from
5 QDs with different emission energy which is due to the increase in the growth rate, and hence, height of
QDs owing to the desorption of group-III adatoms from the NW sidewalls and migration to the NW tips,
as stated in the manuscript. If we tune the growth duration to tailor the height of individual QDs, we
observe the sharp light emission from 5 QDs with improved size distribution as obviously seen in the right
figure of Fig. S1. By contrast, if we counter-tune the growth duration of individual QDs as shown in the
a
E-mail: tatebaya@iis.u-tokyo.ac.jp
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After countertuning
1.25
Growth duration
(b)
1.30 1.35 1.40
Energy (eV)
After tuning
Intensity (a.u.)
Before tuning
Intensity (a.u.)
Intensity (a.u.)
(a)
1.45 1.25
1.30 1.35 1.40
Energy (eV)
1.25
+20%
0%
-20%
+10%
0%
-10%
0%
0%
0%
-10%
0%
+10%
-20%
0%
+20%
Energy(eV)
Energy (eV)
1.30 1.35 1.40
Energy (eV)
1.45
Energy (eV)
Figure S1 (a) -PL spectra at 6K of 5-stack In0.22Ga0.78As/GaAs NWQDs (GaAs spacer of 200 nm)
before and after tuning the growth duration of individual QDs. A center graph shows the spectrum
before tuning the growth duration, Right and left graphs shows the spectra after tuning and countertuning the growth duration, respectively. (b) conceptional illustrations of the procedure to tune the
emission energies of 5 QDs and their resulting spectra.
left figure of Fig. S1, the emission spectrum from 5 QDs exhibits 5 sharp peak with wider broadness.
These results suggest that we are able to control the broadness of PL by carefully tuning the growth
duration of individual QDs in a single NW.
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