Biomedical Engineering Reference
In-Depth Information
Fig. 1.8
Distribution of QD
heights in the QDMs sample
Fig. 1.9
Normalized PL
spectra of single QDs (
red
solid curve
), and QDMs (
blue
solid curve
). Reprinted
(adapted) with permission
from [
20
]. Copyright 2009
American Chemical Society
parallel to this direction that are As-terminated (B-type facets). It is well known
that the incorporation kinetics of Group-III atoms on each type of facets depends
strongly on the experimental growth conditions and, specifically, on the substrate
temperature [
44
], arsenic pressure [
44
-
47
], and type of As used during growth (As
2
or As
4
)[
48
].
In conclusion, in this subsection we have demonstrated that the As
2
pressure
used during InAs material deposition is a key parameter in order to control the
formation of either single QDs or QDMs into previously in situ etched nanoholes.
Under the appropriate conditions occupancy of 98% of the nanoholes with QDMs
can be obtained. In general terms, this result demonstrates that the ability to fabricate
QDMs into patterned nanoholes lies on the understanding of the preferential self-
assembling growth process into them rather than the simply fabrication of a suitable
motif.
1.2.3
Lateral Coupling in a Single QDM
Quantum-mechanical coupling in a lateral QDM has been barely studied exper-
imentally [
16
,
17
]. Previous indications of electronic coupling in a lateral QDM
have been based on an analysis of the anomalous Stark shifts and photon correlation
