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Exciton Molecule Creation by Pure and Phonon‐Assisted Two‐Photon Transitions in Solids
Author(s) -
Hassan A. R.
Publication year - 1978
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.2220870104
Subject(s) - exciton , phonon , absorption (acoustics) , semiconductor , photon , attenuation coefficient , chemistry , condensed matter physics , biexciton , materials science , physics , optoelectronics , quantum mechanics , optics
Direct creation of bi‐exciton states, by direct and phonon‐assisted two‐photon absorption in direct‐ and indirect‐gap semiconductors, is theoretically investigated. A group‐theoretical analysis of the final direct (indirect) bi‐exciton symmetry is given for CuCl(Ge). Numerical applications to the case of CuCl and Si show that the direct and indirect two‐photon absorption coefficient for bi‐excitonic transitions are several orders of magnitude larger than those for the corresponding processes of interband and excitonic transitions. The essential contribution to this enhancement of the absorption coefficient for the transitions to the direct and indirect excitonic molecule states is shown to be from the resonance effect.