Relaxation of nonthermal hh and lh excitons in ZnSe quantum                wells

H. Kalt; J. Hoffmann; M. Umlauff; Wolfgang Werner Langbein; Jørn Märcher Hvam

doi:10.1002/(SICI)1521-3951(199803)206:1<103::AID-PSSB103>3.3.CO;2-F

Relaxation of nonthermal hh and lh excitons in ZnSe quantum wells

H. Kalt, J. Hoffmann, M. Umlauff, Wolfgang Werner Langbein, Jørn Märcher Hvam

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Abstract

The strong exciton-LO phonon coupling in ZnSe QWs gives a direct access to the relaxation dynamics of nonthermal, free heavy-hole and light-hole excitons. Narrow hot-exciton distributions can be generated by LO-phonon assisted exciton formation. The thermalization of these excitons is monitored by cw or time-resolved phonon-sideband spectroscopy. A thermal exciton distribution evolves on a 100 ps timescale at low exciton densities when only scattering with acoustic phonons is possible. Exciton-exciton scattering accelerates the relaxation dynamics at high densities. Filling of the free heavy-hole exciton states and thermal population of the light-hole exciton states is observed. Measurements of the polarization degree after excitation with a sigma(+)-polarized picosecond pulse show that light-hole excitons with zero in-plane momentum change sign of their spin with each emission of an LO phonon.

Original language	English
Journal	IPPS physica status solidi (b)
Volume	206
Issue number	1
Pages (from-to)	103-109
ISSN	0370-1972
DOIs	https://doi.org/10.1002/(SICI)1521-3951(199803)206:1<103::AID-PSSB103>3.3.CO;2-F
Publication status	Published - 1998

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title = "Relaxation of nonthermal hh and lh excitons in ZnSe quantum wells",

abstract = "The strong exciton-LO phonon coupling in ZnSe QWs gives a direct access to the relaxation dynamics of nonthermal, free heavy-hole and light-hole excitons. Narrow hot-exciton distributions can be generated by LO-phonon assisted exciton formation. The thermalization of these excitons is monitored by cw or time-resolved phonon-sideband spectroscopy. A thermal exciton distribution evolves on a 100 ps timescale at low exciton densities when only scattering with acoustic phonons is possible. Exciton-exciton scattering accelerates the relaxation dynamics at high densities. Filling of the free heavy-hole exciton states and thermal population of the light-hole exciton states is observed. Measurements of the polarization degree after excitation with a sigma(+)-polarized picosecond pulse show that light-hole excitons with zero in-plane momentum change sign of their spin with each emission of an LO phonon.",

author = "H. Kalt and J. Hoffmann and M. Umlauff and Langbein, {Wolfgang Werner} and Hvam, {J{\o}rn M{\"a}rcher}",

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TY - JOUR

T1 - Relaxation of nonthermal hh and lh excitons in ZnSe quantum wells

AU - Kalt, H.

AU - Hoffmann, J.

AU - Umlauff, M.

AU - Langbein, Wolfgang Werner

AU - Hvam, Jørn Märcher

PY - 1998

Y1 - 1998

N2 - The strong exciton-LO phonon coupling in ZnSe QWs gives a direct access to the relaxation dynamics of nonthermal, free heavy-hole and light-hole excitons. Narrow hot-exciton distributions can be generated by LO-phonon assisted exciton formation. The thermalization of these excitons is monitored by cw or time-resolved phonon-sideband spectroscopy. A thermal exciton distribution evolves on a 100 ps timescale at low exciton densities when only scattering with acoustic phonons is possible. Exciton-exciton scattering accelerates the relaxation dynamics at high densities. Filling of the free heavy-hole exciton states and thermal population of the light-hole exciton states is observed. Measurements of the polarization degree after excitation with a sigma(+)-polarized picosecond pulse show that light-hole excitons with zero in-plane momentum change sign of their spin with each emission of an LO phonon.

AB - The strong exciton-LO phonon coupling in ZnSe QWs gives a direct access to the relaxation dynamics of nonthermal, free heavy-hole and light-hole excitons. Narrow hot-exciton distributions can be generated by LO-phonon assisted exciton formation. The thermalization of these excitons is monitored by cw or time-resolved phonon-sideband spectroscopy. A thermal exciton distribution evolves on a 100 ps timescale at low exciton densities when only scattering with acoustic phonons is possible. Exciton-exciton scattering accelerates the relaxation dynamics at high densities. Filling of the free heavy-hole exciton states and thermal population of the light-hole exciton states is observed. Measurements of the polarization degree after excitation with a sigma(+)-polarized picosecond pulse show that light-hole excitons with zero in-plane momentum change sign of their spin with each emission of an LO phonon.

U2 - 10.1002/(SICI)1521-3951(199803)206:1<103::AID-PSSB103>3.3.CO;2-F

DO - 10.1002/(SICI)1521-3951(199803)206:1<103::AID-PSSB103>3.3.CO;2-F

M3 - Journal article

SN - 0370-1972

VL - 206

SP - 103

EP - 109

JO - IPPS physica status solidi (b)

JF - IPPS physica status solidi (b)

IS - 1

ER -

Relaxation of nonthermal hh and lh excitons in ZnSe quantum wells

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