Gallium concentration effects on the properties of CuIn1-xGaxSe2 ingots

In this paper, we report on the crystal growth of CuIn1-xGaxSe2 ingots with different gallium concentrations (0 5 x 5 1), and investigate the influence of these concentrations on the structural, optical and electrical properties of these compounds. The preferred orientation in the (112) direction was obtained, and the main XRD peaks showed a noticeable shift to higher diffraction angles with increasing Ga content. The lattice parameters "a" and "c" have been calculated from the X-ray spectra and were found to decrease with the increase of gallium concentration. In addition the c/a ratio was found to be close to 2. The band gap E-g increased when the Ga/(In+Ga) ratios increased. The ingots have p-type conductivity and their resistivity varied between 6.41 and 32.64 Omega cm with a minimum value of 0.67 Omega cm for x=0.4.