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High‐pressure photoluminescence study of the electronic structure of InP/GaP quantum dots
Author(s) -
Kristukat C.,
Goñi A.R.,
Hatami F.,
Dreßler S.,
Masselink W.T.,
Thomsen C.
Publication year - 2003
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/pssb.200301593
Subject(s) - photoluminescence , hydrostatic pressure , quantum dot , condensed matter physics , band gap , materials science , redshift , electron , conduction band , electronic structure , exciton , optoelectronics , physics , quantum mechanics , galaxy , thermodynamics
The electronic subband structure of self‐assembled InP/GaP quantum dots (QDs) has been investigated by means of photoluminescence (PL) measurements as a function of hydrostatic pressure up to 8 GPa and temperature. At ambient pressure the PL emission of the sample arises from direct optical transitions between the lowest electron and hole Γ‐point states confined in the QDs. At a very low pressure of about 0.15 GPa, the Γ–X conduction band crossover occurs, after which the PL emission of the dots becomes roughly 20 times weaker in intensity and its energy exhibits the slight redshift typical of indirect recombination processes from the conduction band X valleys. Our results indicate a type‐I band alignment for the strained InP/GaP dot structure at low pressure and yield a value of 300 ± 30 meV for the valence‐band offset.