Nonstoichiometry of CuInSe2 and method of controlled atomic defects Original Research Article

The results of a complex study of the crystal structure, mechanical, galvanomagnetic and thermoelectric properties of CuInSe2 under different schemes and degrees of deviation from stoichiometry are presented. Nonstoichiometric compositions for studies were selected using the method of ‘controlled atomic defects’. The solubility limits of extrastoichiometric dopants (Se, CuIn, InSe, CuSe2, InSe2 and In2Se3) are determined, and the types of predominant intrinsic defects corresponding to different schemes of deviation from stoichiometry are identified. On the basis of the temperature dependences of the galvanomagnetic properties, positions of energy levels created by nonstoichiometric defects of different types (Cu, In and Se vacancies, CuIn and InCu substitution defects, Se interstitials) are determined. The correlation between composition, type and concentration of nonstoichiometric defects, structure and properties of CuInSe2 under various modes of deviation from stoichiometry is established.