Crystal Growth and Properties of the Compounds CuGa3Se5 and CuIn3Se5

CuIn3Se5 and CuGa3Se5 uniform single crystals 12 mm in diameter and 40 mm in length with the chalcopyrite‐related structure were prepared by directed crystallization of the melt. The melting points of these compounds were defined by means of the differential thermal analysis (DTA). The lattice parameters a and c as well as the axial thermal expansion coefficients αa and αc were determined as a function of temperature in the range from 90 to 650 K by the X‐ray diffraction method (XRD). It is found that for both the compounds the coefficients of expansion along the a‐axis are larger than those along the c‐axis over the entire temperature range studied.