Growth and optical properties of strain-induced quantum dots

Harri Lipsanen, Markku Sopanen, J. Tulkki, Jouni Ahopelto, M. Brasken, M. Lindberg

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

In recent years, high-quality quantum dots (QD) have been fabricated using self-organized island growth of strained layers, e.g., InAs on GaAs. In our approach, self-organized InP islands are used as stressors on top of a near-surface quantum well (QW), typically an InGaAs/GaAs QW. The strain field of the InP island causes a nearly parabolic lateral potential below the island. Vertical confinement is obtained by the QW potential. The QD structure can be easily tailored by changing the QW composition and thickness, the distance of the QW from the InP stressor, or the size of the stressors by varying the growth temperature. Furthermore, coupled QDs and QD superlattices have been fabricated by introducing two or more QWs into the structure. Narrow linewidth QD ground and excited state transitions are obtained by low-temperature photoluminescence (PL). The experimental transition energies agree well with the theoretical modeling based on the finite element method. Time-resolved luminescence experiments yield a radiative recombination time of 0.9 ns and an interlevel relaxation time of 0.6 ns for the electrons. PL up-conversion experiments show a fast rise time of ~ 1 ps for all QD transitions, which suggests that Coulomb scattering is the dominant scattering mechanism in the initial stage in agreement with the modeling. The effect of magnetic field on the optical properties of the QDs has been studied using a field up to 8 T, where a large Zeeman splitting of the excited QD states has been observed in agreement with a single-particle model.
Original languageEnglish
Pages (from-to)20-26
Number of pages7
JournalPhysica Scripta
Issue numberT79
DOIs
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

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Quantum Dots
Optical Properties
Quantum Well
quantum dots
optical properties
quantum wells
Photoluminescence
Gallium Arsenide
Scattering
photoluminescence
Upconversion
InGaAs
Superlattices
Luminescence
Excited States
Linewidth
radiative recombination
State Transition
scattering
Modeling

Cite this

Lipsanen, H., Sopanen, M., Tulkki, J., Ahopelto, J., Brasken, M., & Lindberg, M. (1999). Growth and optical properties of strain-induced quantum dots. Physica Scripta, (T79), 20-26. https://doi.org/10.1238/Physica.Topical.079a00020
Lipsanen, Harri ; Sopanen, Markku ; Tulkki, J. ; Ahopelto, Jouni ; Brasken, M. ; Lindberg, M. / Growth and optical properties of strain-induced quantum dots. In: Physica Scripta. 1999 ; No. T79. pp. 20-26.
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Lipsanen, H, Sopanen, M, Tulkki, J, Ahopelto, J, Brasken, M & Lindberg, M 1999, 'Growth and optical properties of strain-induced quantum dots', Physica Scripta, no. T79, pp. 20-26. https://doi.org/10.1238/Physica.Topical.079a00020

Growth and optical properties of strain-induced quantum dots. / Lipsanen, Harri; Sopanen, Markku; Tulkki, J.; Ahopelto, Jouni; Brasken, M.; Lindberg, M.

In: Physica Scripta, No. T79, 1999, p. 20-26.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Growth and optical properties of strain-induced quantum dots

AU - Lipsanen, Harri

AU - Sopanen, Markku

AU - Tulkki, J.

AU - Ahopelto, Jouni

AU - Brasken, M.

AU - Lindberg, M.

PY - 1999

Y1 - 1999

N2 - In recent years, high-quality quantum dots (QD) have been fabricated using self-organized island growth of strained layers, e.g., InAs on GaAs. In our approach, self-organized InP islands are used as stressors on top of a near-surface quantum well (QW), typically an InGaAs/GaAs QW. The strain field of the InP island causes a nearly parabolic lateral potential below the island. Vertical confinement is obtained by the QW potential. The QD structure can be easily tailored by changing the QW composition and thickness, the distance of the QW from the InP stressor, or the size of the stressors by varying the growth temperature. Furthermore, coupled QDs and QD superlattices have been fabricated by introducing two or more QWs into the structure. Narrow linewidth QD ground and excited state transitions are obtained by low-temperature photoluminescence (PL). The experimental transition energies agree well with the theoretical modeling based on the finite element method. Time-resolved luminescence experiments yield a radiative recombination time of 0.9 ns and an interlevel relaxation time of 0.6 ns for the electrons. PL up-conversion experiments show a fast rise time of ~ 1 ps for all QD transitions, which suggests that Coulomb scattering is the dominant scattering mechanism in the initial stage in agreement with the modeling. The effect of magnetic field on the optical properties of the QDs has been studied using a field up to 8 T, where a large Zeeman splitting of the excited QD states has been observed in agreement with a single-particle model.

AB - In recent years, high-quality quantum dots (QD) have been fabricated using self-organized island growth of strained layers, e.g., InAs on GaAs. In our approach, self-organized InP islands are used as stressors on top of a near-surface quantum well (QW), typically an InGaAs/GaAs QW. The strain field of the InP island causes a nearly parabolic lateral potential below the island. Vertical confinement is obtained by the QW potential. The QD structure can be easily tailored by changing the QW composition and thickness, the distance of the QW from the InP stressor, or the size of the stressors by varying the growth temperature. Furthermore, coupled QDs and QD superlattices have been fabricated by introducing two or more QWs into the structure. Narrow linewidth QD ground and excited state transitions are obtained by low-temperature photoluminescence (PL). The experimental transition energies agree well with the theoretical modeling based on the finite element method. Time-resolved luminescence experiments yield a radiative recombination time of 0.9 ns and an interlevel relaxation time of 0.6 ns for the electrons. PL up-conversion experiments show a fast rise time of ~ 1 ps for all QD transitions, which suggests that Coulomb scattering is the dominant scattering mechanism in the initial stage in agreement with the modeling. The effect of magnetic field on the optical properties of the QDs has been studied using a field up to 8 T, where a large Zeeman splitting of the excited QD states has been observed in agreement with a single-particle model.

U2 - 10.1238/Physica.Topical.079a00020

DO - 10.1238/Physica.Topical.079a00020

M3 - Article

SP - 20

EP - 26

JO - Physica Scripta

JF - Physica Scripta

SN - 0031-8949

IS - T79

ER -