Anisotropic thermal expansion of copper gallium selenide

Abstract
Unit-cell parameters for the chalcopyrite type ternary semiconducting compound copper gallium selenide (CuGaSe2) have been determined accurately, using the least-squares method, for reflections in the range of Bragg angles 64-82 degrees , by the X-ray powder diffraction method. A study of the thermal expansion of the chalcopyrite structure unit-cell of the compound, determined over the temperature range 28-685 degrees C, has revealed the anisotropy between the axial expansion coefficients; that for the c axis (24.93*10-6 degrees C-1) is about four times that for the a axis (5.91*10-6 degrees C-1) at 50 degrees C. Anomalous behaviour of the expansion coefficients, similar to that for AgInSe2, AgGaSe2 and AgGaS2, has not been observed for this compound.