Size and shape engineering of vertically stacked self-assembled quantum dots

doi:10.1016/S0022-0248(98)01539-5

Journal of Crystal Growth

Volumes 201–202, May 1999, Pages 1131-1135

https://doi.org/10.1016/S0022-0248(98)01539-5 Get rights and content

Abstract

A new procedure for the growth of stacked self-assembled quantum dot layers is described. The main effect of the procedure is to convert the quantum dot population into a population of quantum disks of approximately equal height. Proposed model of the overgrowth process for highly strained 3D islands invokes mechanisms which may lead to a variety of dot shape modification and opens up new ways of influencing the dot population by deliberate control of the overgrowth process. Demonstrated very good performance of test devices indicate that the proposed procedure may have positive impact on the further development of quantum dot lasers.

References (22)

Y. Nakata et al.
J. Crystal Growth
(1997)
S. Fafard et al.
Material Science and Engineering
(1998)
R.P. Mirin et al.
J. Crystal Growth
(1997)
Z.R. Wasilewski et al.
J. Crystal Growth
(1997)
L. Goldstein et al.
Appl. Phys. Lett.
(1985)
R. Notzel et al.
Jpn. J. Appl. Phys.
(1994)
Q. Xie et al.
Phys. Rev. Lett.
(1995)
N.N. Ledentsov et al.
Phys. Rev. B
(1996)
G.S. Solomon et al.
Phys. Rev. Lett.
(1996)
W. Wu et al.
Appl. Phys. Lett.
(1997)

R. Heitz et al.

Phys. Rev.

(1998)

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Size and shape engineering of vertically stacked self-assembled quantum dots

Abstract

J. Crystal Growth

Material Science and Engineering

J. Crystal Growth

J. Crystal Growth

Appl. Phys. Lett.

Jpn. J. Appl. Phys.

Phys. Rev. Lett.

Phys. Rev. B

Phys. Rev. Lett.

Appl. Phys. Lett.

Phys. Rev.