Structural and optical characterization of homogeneous monophasic Cu(In1-xGax)(Se1-ySy)2 thin films

Single-phase Cu(In1-xGax)(Se1-ySy)(2) thin-film absorbers have been prepared by a reproducible two-stage growth method. The growth scheme is based on the selenization/sulfurization of metallic CuIn0.75Ga0.25 alloys in an atmosphere containing a mixture of H2Se/H2S/Ar gases. The degree of S incorporation was carefully controlled by the accurate manipulation of the H2Se/H2S reaction process parameters under defined conditions. Using this novel approach, pentenary alloys with varying degree of S content (i.e. S/(Se+S) ratio = 0.1-0.5) were prepared. A systematic study was conducted in order to establish the relationship between the morphological features, lattice parameters and band gap values of these classes of semiconductor materials. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.