Role of Symmetry Breaking on the Optical Transitions in Lead-Salt Quantum Dots

Gero Nootz; Lazaro A. Padilha; Peter D. Olszak; Scott Webster; David J. Hagan; Eric W. Van Stryland; Larissa Levina; Vlad Sukhovatkin; Lukasz Brzozowski; Edward H. Sargent

doi:10.1021/nl1018673

Role of Symmetry Breaking on the Optical Transitions in Lead-Salt Quantum Dots

Gero Nootz, Lazaro A. Padilha, Peter D. Olszak, Scott Webster, David J. Hagan, Eric W. Van Stryland, Larissa Levina, Vlad Sukhovatkin, Lukasz Brzozowski, Edward H. Sargent

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Abstract

The influence of quantum confinement on the one- and two-photon absorption spectra (1PA and 2PA) of PbS and PbSe semiconductor quantum dots (QDs) is investigated. The results show 2PA peaks at energies where only 1PA transitions are predicted and 1PA peaks where only 2PA transitions are predicted by the often used isotropic k•p four-band envelope function formalism. The first experimentally identified two-photon absorption peak coincides with the energy of the first one photon allowed transition. This first two-photon peak cannot be explained by band anisotropy, verifying that the inversion symmetry of the wave functions is broken and relaxation of the parity selection rules has to be taken into account to explain optical transitions in lead-salt QDs. Thus, while the band anisotropy of the bulk semiconductor plays a role in the absorption spectra, especially for the more anisotropic PbSe QDs, a complete model of the absorption spectra, for both 1PA and 2PA, must also include symmetry breaking of the quantum confined wave functions. These studies clarify the controversy of the origin of spectral features in lead-salt QDs. © 2010 American Chemical Society.

Original language	English (US)
Pages (from-to)	3577-3582
Number of pages	6
Journal	Nano Letters
Volume	10
Issue number	9
DOIs	https://doi.org/10.1021/nl1018673
State	Published - Sep 8 2010
Externally published	Yes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-I1-009-21
Acknowledgements: This material is based upon work supported in part by the U.S. Army Research Office under Contract/Grant 50372-CH-MUR, the Air Force Office of Sponsored Research MURI AFOSR Grant FA9550-06-1-0337, the DARPA ZOE program Grant W31R4Q-09-1-0012, and the Israel Ministry of Defense contract 993/54250-01 and by Award No. KUS-I1-009-21, made by King Abdullah University of Science and Technology (KAUST). We also would like to thank Frank W. Wise for helpful discussions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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10.1021/nl1018673

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@article{58302cb6c105438b97a19d42e14a2203,

title = "Role of Symmetry Breaking on the Optical Transitions in Lead-Salt Quantum Dots",

abstract = "The influence of quantum confinement on the one- and two-photon absorption spectra (1PA and 2PA) of PbS and PbSe semiconductor quantum dots (QDs) is investigated. The results show 2PA peaks at energies where only 1PA transitions are predicted and 1PA peaks where only 2PA transitions are predicted by the often used isotropic k•p four-band envelope function formalism. The first experimentally identified two-photon absorption peak coincides with the energy of the first one photon allowed transition. This first two-photon peak cannot be explained by band anisotropy, verifying that the inversion symmetry of the wave functions is broken and relaxation of the parity selection rules has to be taken into account to explain optical transitions in lead-salt QDs. Thus, while the band anisotropy of the bulk semiconductor plays a role in the absorption spectra, especially for the more anisotropic PbSe QDs, a complete model of the absorption spectra, for both 1PA and 2PA, must also include symmetry breaking of the quantum confined wave functions. These studies clarify the controversy of the origin of spectral features in lead-salt QDs. {\textcopyright} 2010 American Chemical Society.",

author = "Gero Nootz and Padilha, {Lazaro A.} and Olszak, {Peter D.} and Scott Webster and Hagan, {David J.} and {Van Stryland}, {Eric W.} and Larissa Levina and Vlad Sukhovatkin and Lukasz Brzozowski and Sargent, {Edward H.}",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledged KAUST grant number(s): KUS-I1-009-21 Acknowledgements: This material is based upon work supported in part by the U.S. Army Research Office under Contract/Grant 50372-CH-MUR, the Air Force Office of Sponsored Research MURI AFOSR Grant FA9550-06-1-0337, the DARPA ZOE program Grant W31R4Q-09-1-0012, and the Israel Ministry of Defense contract 993/54250-01 and by Award No. KUS-I1-009-21, made by King Abdullah University of Science and Technology (KAUST). We also would like to thank Frank W. Wise for helpful discussions. This publication acknowledges KAUST support, but has no KAUST affiliated authors.",

year = "2010",

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doi = "10.1021/nl1018673",

language = "English (US)",

volume = "10",

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T1 - Role of Symmetry Breaking on the Optical Transitions in Lead-Salt Quantum Dots

AU - Nootz, Gero

AU - Padilha, Lazaro A.

AU - Olszak, Peter D.

AU - Webster, Scott

AU - Hagan, David J.

AU - Van Stryland, Eric W.

AU - Levina, Larissa

AU - Sukhovatkin, Vlad

AU - Brzozowski, Lukasz

AU - Sargent, Edward H.

N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledged KAUST grant number(s): KUS-I1-009-21 Acknowledgements: This material is based upon work supported in part by the U.S. Army Research Office under Contract/Grant 50372-CH-MUR, the Air Force Office of Sponsored Research MURI AFOSR Grant FA9550-06-1-0337, the DARPA ZOE program Grant W31R4Q-09-1-0012, and the Israel Ministry of Defense contract 993/54250-01 and by Award No. KUS-I1-009-21, made by King Abdullah University of Science and Technology (KAUST). We also would like to thank Frank W. Wise for helpful discussions. This publication acknowledges KAUST support, but has no KAUST affiliated authors.

PY - 2010/9/8

Y1 - 2010/9/8

N2 - The influence of quantum confinement on the one- and two-photon absorption spectra (1PA and 2PA) of PbS and PbSe semiconductor quantum dots (QDs) is investigated. The results show 2PA peaks at energies where only 1PA transitions are predicted and 1PA peaks where only 2PA transitions are predicted by the often used isotropic k•p four-band envelope function formalism. The first experimentally identified two-photon absorption peak coincides with the energy of the first one photon allowed transition. This first two-photon peak cannot be explained by band anisotropy, verifying that the inversion symmetry of the wave functions is broken and relaxation of the parity selection rules has to be taken into account to explain optical transitions in lead-salt QDs. Thus, while the band anisotropy of the bulk semiconductor plays a role in the absorption spectra, especially for the more anisotropic PbSe QDs, a complete model of the absorption spectra, for both 1PA and 2PA, must also include symmetry breaking of the quantum confined wave functions. These studies clarify the controversy of the origin of spectral features in lead-salt QDs. © 2010 American Chemical Society.

AB - The influence of quantum confinement on the one- and two-photon absorption spectra (1PA and 2PA) of PbS and PbSe semiconductor quantum dots (QDs) is investigated. The results show 2PA peaks at energies where only 1PA transitions are predicted and 1PA peaks where only 2PA transitions are predicted by the often used isotropic k•p four-band envelope function formalism. The first experimentally identified two-photon absorption peak coincides with the energy of the first one photon allowed transition. This first two-photon peak cannot be explained by band anisotropy, verifying that the inversion symmetry of the wave functions is broken and relaxation of the parity selection rules has to be taken into account to explain optical transitions in lead-salt QDs. Thus, while the band anisotropy of the bulk semiconductor plays a role in the absorption spectra, especially for the more anisotropic PbSe QDs, a complete model of the absorption spectra, for both 1PA and 2PA, must also include symmetry breaking of the quantum confined wave functions. These studies clarify the controversy of the origin of spectral features in lead-salt QDs. © 2010 American Chemical Society.

UR - http://hdl.handle.net/10754/599534

UR - https://pubs.acs.org/doi/10.1021/nl1018673

UR - http://www.scopus.com/inward/record.url?scp=77956446908&partnerID=8YFLogxK

U2 - 10.1021/nl1018673

DO - 10.1021/nl1018673

M3 - Article

C2 - 20734976

SN - 1530-6984

VL - 10

SP - 3577

EP - 3582

JO - Nano Letters

JF - Nano Letters

IS - 9

ER -

Role of Symmetry Breaking on the Optical Transitions in Lead-Salt Quantum Dots

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