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Temperature dependence of ESR spectra of doped a‐Si:H
Author(s) -
Dersch H.,
Stuke J.,
Beichler J.
Publication year - 1981
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.2221070132
Subject(s) - condensed matter physics , doping , valence (chemistry) , density of states , electron , electrical resistivity and conductivity , boron , conductivity , chemistry , thermal conduction , relaxation (psychology) , spectral line , activation energy , band gap , materials science , analytical chemistry (journal) , physics , chromatography , psychology , social psychology , organic chemistry , quantum mechanics , astronomy , composite material
The temperature dependence of the ESR lines with g = 2.01 for boron‐doped and with g = 2.0043 for phosphorus‐doped a–Si:H, associated with singly occupied tail states of the valence and conduction band, respectively, is investigated. Both resonances broaden considerably with increasing temperature, and the broadening δ H pp ( T ) is related with the electrical conductivity σ( T ) as δ H pp ( T ) = c[σ( T ] n with 0.64 < n < 1. The g ‐values of both lines decrease with rising temperature. The spin density N 8 is for weakly boron‐doped samples constant at low temperatures, for phosphorus‐doped a‐Si: H, however, an increase of N 8 with rising temperature is observed. These results are explained in a model with a small correlation energy ( U < kT ) for the conduction band tail and a large one ( U ≫ kT ) for the valence band tail. The temperature variation of the g ‐value is ascribed to its energy dependence. Electrons in localized states near the mobility edges are assumed to have smaller g ‐values than those in states with a larger energy distance from the edges. The relation between the line broadening δ H pp ( T ) and the conductivity can be understood by spin relaxation of the localized electrons due to exchange coupling with rapidly relaxing carriers in extended states.