4 research outputs found
Exciton-relaxation dynamics in lead halides
We survey recent comprehensive studies of exciton relaxation in the crystals
of lead halides. The luminescence and electron-spin-resonance studies have
revealed that excitons in lead bromide spontaneously dissociate and both
electrons and holes get self-trapped individually. Similar relaxation has been
also clarified in lead chloride. The electron-hole separation is ascribed to
repulsive correlation via acoustic phonons. Besides, on the basis of the
temperature profiles of self-trapped states, we discuss the origin of
luminescence components which are mainly induced under one-photon excitation
into the exciton band in lead fluoride, lead chloride, and lead bromide.Comment: REVTeX, 5 pages, 5 figure
Self-trapped electrons and holes in PbBr crystals
We have directly observed self-trapped electrons and holes in PbBr
crystals with electron-spin-resonance (ESR) technique. The self-trapped states
are induced below 8 K by two-photon interband excitation with pulsed
120-fs-width laser light at 3.10 eV. Spin-Hamiltonian analyses of the ESR
signals have revealed that the self-trapping electron centers are the dimer
molecules of Pb along the crystallographic a axis and the
self-trapping hole centers are those of Br with two possible
configurations in the unit cell of the crystal. Thermal stability of the
self-trapped electrons and holes suggests that both of them are related to the
blue-green luminescence band at 2.55 eV coming from recombination of spatially
separated electron-hole pairs.Comment: 8 pages (7 figures, 2 tables), ReVTEX; revised the text and figures
1, 4, and
Self-trapped states and the related luminescence in PbCl crystals
We have comprehensively investigated localized states of photoinduced
electron-hole pairs with electron-spin-resonance technique and
photoluminescence (PL) in a wide temperature range of 5-200 K. At low
temperatures below 70 K, holes localize on Pb ions and form
self-trapping hole centers of Pb. The holes transfer to other trapping
centers above 70 K. On the other hand, electrons localize on two Pb ions
at higher than 50 K and form self-trapping electron centers of Pb.
From the thermal stability of the localized states and PL, we clarify that
blue-green PL band at 2.50 eV is closely related to the self-trapped holes.Comment: 8 pages (10 figures), ReVTEX; removal of one figure, Fig. 3 in the
version
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京都大学0048新制・論文博士理学博士乙第3474号論理博第593号新制||理||269(附属図書館)UT51-52-N115(主査)教授 中井 祥夫, 教授 浅井 健次郎, 教授 端 恒夫学位規則第5条第2項該当Kyoto UniversityDFA