Structural and optical properties of CuIn1-xGaxSe2 thin films

Bulk alloys of CuIn1-xGaxSe2 with Ga – incorporation ratio x= Ga / (Ga + In) equal to 0.1, 0.2, 0.3, 0.4 and 0.6 have been prepared by the melt quench technique. The CuIn1-xGaxSe2 (CIGS) thin films have been deposited on clean microscope glass substrates with different thickness (50, 100, 150, 200 and 250 nm) using the thermally evaporated technique in a vacuum of 3x10-4 mbar from the prepared bulk material. XRD, SEM and EDAX were utilized in order to examine the structure, surface morphology and composition stoichiometry of CIGS samples. Effects of Ga – ratio, film thickness and annealing at 573 K for different periods of time (5 – 60 min.) on structural and optical properties have been depicted and explained. Some important structural and optical parameters were calculated and discussed.