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Optical and Photoelectrical Properties of β‐Rhombohedral Boron II. Photoeffects
Author(s) -
Werheit H.
Publication year - 1970
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.19700390112
Subject(s) - boron , ionization , absorption edge , electron , atomic physics , absorption (acoustics) , ionization energy , semiconductor , infrared , conduction band , trapping , materials science , opacity , trigonal crystal system , chemistry , band gap , ion , optoelectronics , optics , physics , crystal structure , organic chemistry , quantum mechanics , composite material , biology , crystallography , ecology
β‐rhombohedral boron is characterized as infrared phosphor. Below 100 °C the optical absorption in the region between absorption edge and lattice vibrations as well as the electrical conductivity show a considerable rise during illumination with white light caused by two trapping levels of great density of states. At low temperatures both levels cannot be occupied simultaneously. Optical ionization spectra of charged traps (“photoabsorption”) give high activation energies confirmed by glow curves derived from the temperature dependence of photoabsorption. The recombination of trapped electrons and free holes does not take place directly but via the conduction band. Therefore it is considerably delayed especially at low temperatures because of the high ionization energies of the traps.