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Dynamics of trapping on donors and relaxation of the B‐exciton in GaN
Author(s) -
Korona K. P.,
Wysmołek A.,
Stępniewski R.,
Potemski M.,
Kuhl J.,
Baranowski J. M.,
Martinez G.,
Grzegory I.,
Porowski S.
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.200301526
Subject(s) - exciton , biexciton , excitation , relaxation (psychology) , trapping , photoluminescence , binding energy , atomic physics , chemistry , spectroscopy , condensed matter physics , magnetic field , materials science , physics , optoelectronics , quantum mechanics , psychology , social psychology , ecology , biology
There are three exciton branches in wurzite‐GaN: A, B and C. Here, time‐resolved photoluminescence and magneto‐optic spectroscopy of the B‐exciton are presented, both free (FX B ) and bound to donor (D 0 X B ) in homoepitaxial GaN. The free B‐exciton has an energy of about 3.483 eV and a very short lifetime of about 20 ps. The B‐exciton bound to donor (D 0 X B ) has an energy of 3.475 eV and a lifetime longer than the free excitons but shorter than the lifetime of the A‐exciton bound to donor. It is shown that a simple model based on an invariant expression describes properly the behavior of D 0 X A and D 0 X B in a magnetic field. Results of resonance excitation experiments suggest that in many cases the process of binding a free exciton to a donor conserves the exciton type and that the relaxation of B‐ to A‐exciton takes place later. Moreover, thermal excitation of D 0 X A to D 0 X B has been observed.