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Determination of exciton diffusion length from photoconductivity low‐temperature spectra
Author(s) -
Novikov B. V.,
Ilinskii A. V.,
Lieder K. F.,
Sokolov N. S.
Publication year - 1971
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.2220480204
Subject(s) - exciton , photoconductivity , diffusion , photocurrent , spectral line , materials science , range (aeronautics) , atmospheric temperature range , absorption (acoustics) , molecular physics , absorption spectroscopy , surface photovoltage , analytical chemistry (journal) , spectroscopy , chemistry , condensed matter physics , optics , optoelectronics , physics , thermodynamics , chromatography , quantum mechanics , astronomy , composite material
The spectral distribution of the photoconductivity of CdS and CdSe single crystals has been investigated at 77 °K in a wide spectral range. The values of the exciton diffusion lengths in these compounds have been obtained from the photocurrent spectra using the absorption coefficient data. The exciton diffusion lengths were found to be within the range of 2000 to 10000 Å for CdS and 2000 to 4000 Å for CdSe. The proposed model involves the diffusion of the excitons to the surface, where they dissociate into free carriers interacting with the near‐to‐surface centres. The role of the space charge layer in these phenomena is discussed.