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The nature of silver impurity atoms in antimony telluride
Author(s) -
Horák J.,
Lošťák P.,
Šiška L.,
Stordeur M.
Publication year - 1982
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.2221140104
Subject(s) - antimony , hall effect , analytical chemistry (journal) , impurity , dopant , materials science , atom (system on chip) , doping , seebeck coefficient , electrical resistivity and conductivity , chemistry , thermal conductivity , metallurgy , optoelectronics , organic chemistry , chromatography , computer science , electrical engineering , composite material , embedded system , engineering
Undoped Sb 2 Te 3 and Ag‐doped Sb 2 Te 3 crystals are grown by a modified Bridgman method. Electrical conductivity, Seebeck coefficient, Hall constant, and reflectivity in the region of the plasma resonance frequency are measured. A quantitative analysis of the silver content in the prepared Sb 2 Te 3 crystals is made by atomic absorption spectrometry. For the undoped Sb 2 Te 3 crystals the free carrier concentration and the effective mass in the direction perpendicular to the c ‐axis, m ⟂, are calculated, using a simplified model. Using m ⟂ determined and the value of the plasma resonance frequency the free carrier concentration in the Sb 2 Te 3 (Ag) crystals is calculated. According to the results obtained the Ag atoms incorporated into Sb 2 Te 3 crystals have the character of acceptors and the addition of one Ag atom corresponds to the increase in free carrier concentration by two holes. Therefore it is assumed that silver atoms substitute antimony atoms forming thus point defects of Ag″ sb with two negative charges. The defects formed by Ag dopants in Sb 2 Te 3 are compared with those in Bi 2 Se 3 (Ag) and Bi 2 Te 3 (Ag) crystals.