Amorphous arsenic chalcogenide films modified using rare-earth complexes

The optical absorption and current-voltage characteristic of amorphous arsenic chalcogenide As2X3 (X = S, Se) films modified by rare-earth complexes with organic mixed-ligands have been studied. The following two types of complexes were used: europium dipivaloylmethanate Eu(thd)(3) and lanthanide diethyldithiocarbamates Ln(ddtc)(3) (Ln = Pr, Eu). It was shown that the use of rare-earth mixed-complexes with similar volatility to the chalcogenide volatility permits the deposition of amorphous films by thermal evaporation. The decrease in absorption coefficient at the Urbach's edge after introduction of the europium dipivaloylmethanate complexes containing oxygen in arsenic selenide has been revealed. The type of organic ligands, incorporated in the amorphous matrix, determines the shape of current-voltage characteristic. The observed results have been discussed on the basis of the different rigidity of the structure of amorphous arsenic chalcogenides. (c) 2006 Elsevier B.V. All rights reserved.