In this paper we present the structural and optical properties of Cu(In1-xGax)3Se5 ternary and quaternary compounds crystals fabricated by horizontal Bridgman technique. The Cu(In1-xGax)3Se5 materials were characterized by Energy Dispersive Spectrometry (EDS), hot point probe method, X-ray diffraction, Photoluminescence (PL), and Optical response (Photoconductivity). The Cu(In1-xGax)3Se5 have an Ordered Vacancy Chalcopyrite-type structure with lattice constants varying as a function of the x composition.
A good stœchiometry given by the EDS characterization method is well observed in our samples and its magnitude deviation Δy is slight; so, our samples present a nearly perfect stœchiometry (Δy = 0) .
X-Ray diffraction patterns show the presence of many preferential orientations according to the planes (112), (220) and (312) of all the samples . Also, it shows a linear shifting of peaks towards the higher magnitudes of 2θ when the x composition increases. These compounds can be of stanite structure  or an Ordered Vacancy Chalcopyrite structure (OVC)  or Ordered Defect Chalcopyrite Structure (ODC).
We observe a large shift of the main PL and optical response emission peak versus x composition. The band gap energy of Cu(In1-xGax)3Se5 compounds is found to vary from 1.23 eV to 1.85 eV as a function of x.
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