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High temperature electrical properties of CdTe〈Pb〉 crystals under Te saturation
Author(s) -
Fochuk P.,
Grill R.,
Kadys A.,
Jarasiunas K.,
Verstraeten D.,
Feychuk P.,
Parfenyuk O.,
Panchuk O.
Publication year - 2007
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.200675125
Subject(s) - acceptor , electrical resistivity and conductivity , photoexcitation , cadmium telluride photovoltaics , photoconductivity , analytical chemistry (journal) , crystallographic defect , saturation (graph theory) , conductivity , electron , materials science , crystallography , chemistry , condensed matter physics , atomic physics , optoelectronics , physics , mathematics , quantum mechanics , chromatography , combinatorics , excited state
The point defect equilibrium of CdTe〈Pb〉 single crystals under well‐defined Te vapor pressure was investigated up to 1070 K. At 630–900 K these crystals showed p‐type conductivity and at higher temperatures – native n‐type one. During measurements the hole density reached up to ∼2 × 10 17 cm –3 at 800 K. The main acceptor dominant species, which determined the electrical properties of crystals, was supposed to be the (Pb $ ^+_{\rm Cd} $ V $ ^{2-}_{\rm Cd} $ ) – associate with its level in the gap located at E V + 0.42–0.45 eV. Above 900 K native electrons began to influence the conductivity type. Three models of point defect structure were used to describe the galvanomagnetic data – (i) frozen defect structure, (ii) defect structure with shallow or deep acceptor levels fixed during thermal cycles and native defects being in three‐phase solid–liquid–gas (SLG) equilibrium, and (iii) defect structure without any fixed energy level and defect densities being determined by the SLG equilibrium. The FWM technique confirmed p‐type photoconductivity at 300 K, but also revealed bipolar carrier generation at high photoexcitation levels with very fast electron trapping. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)