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Correlated Variable Range Hopping in Doped GaAs, CdTe, Ge and Si
Author(s) -
Rentzsch R.,
Ionov A.N.
Publication year - 2002
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 - 10.1002/1521-3951(200203)230:1<183::aid-pssb183>3.0.co;2-s
Subject(s) - doping , germanium , condensed matter physics , cadmium telluride photovoltaics , variable range hopping , electrical resistivity and conductivity , dielectric , electron , coulomb , materials science , analytical chemistry (journal) , chemistry , silicon , physics , nanotechnology , optoelectronics , quantum mechanics , chromatography
A comparison is reported between the variable‐range hopping resistivity (vrh) of chemically (CdTe : Cl, Si : (As), P, B) or neutron transmutation doped (NTD) (GaAs : Ge, Se; Ge : As, Ga) crystals which is: ϱ ( T ) = ϱ 0 exp ( T 0 / T ) 1/2 with the one‐electron expression of Efros and Shklovskii: ϱ ( T ) = ϱ 0 exp ( T ES / T ) 1/2 . In the dilute limit of small doping concentrations N ≪ N c ( N c is the critical doping concentration of the metal–insulator transition) and low or medium compensation K , the experimentally found values of T 0 are much smaller than T ES . This can be due to many‐particle excitations which reduce the Coulomb gap width. In isotopically engineered (IE) NTD‐p‐Ge at very high K = 0.9, where a large scale potential relief exists, a good agreement was found: T 0 ≅ T ES = 2.8 e 2 / k B a B 4 πε 0 κ 0 ( a B is the localization length and ϰ the dielectric constant). The one‐electron theory seems to be a good approximation in this case.