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Spectroscopic Evidence for the Exciton Percolation Threshold in Low‐Dimensional ZnCdSe Solutions with Nano‐Islands
Author(s) -
Reznitsky A.,
Klochikhin A.,
Permogorov S.,
Tenishev L.,
Sedova I.,
Sorokin S.,
Ivanov S.,
Schmidt M.,
Zhao H.,
Kurtz E.,
Kalt H.,
Klingshirn C.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200201)229:1<509::aid-pssb509>3.0.co;2-g
Subject(s) - exciton , photoluminescence , excitation , spectral line , photoluminescence excitation , quantum well , percolation (cognitive psychology) , luminescence , condensed matter physics , divergence (linguistics) , percolation threshold , monolayer , molecular physics , materials science , chemistry , physics , optoelectronics , optics , nanotechnology , quantum mechanics , electrical resistivity and conductivity , laser , linguistics , philosophy , neuroscience , biology
We have studied photoluminescence (PL), PL excitation (PLE), and micro‐PL spectra of single quantum wells (QWs) formed by CdSe insertions in ZnSe matrix with different nominal Cd thickness (1–3 monolayers (ML)). The PL spectra are considerably red‐shifted with respect to the position expected for homogeneous Cd distribution over the QW and can be attributed to the luminescence of CdSe‐rich islands. It has been found that PLE spectra of different points of the PL band show a characteristic divergence at excitation below some characteristic energy E ME . This energy is identified with the percolation threshold above which the exciton is able to move over the whole lateral plane of QW whereas below the E ME only a resonant excitation of island related states is possible.