Structural and optical properties of CuInxGa1-xSe2 thin films prepared by flash evaporation

Culn(x)Ga(1-x)Se(2) (CIGSe) thin films with x = 0.5 and 0.75 were deposited by a single source vacuum thermal evaporated method 'Flash' on molybdenum coated glass. Some of these films were annealed in selenium atmosphere. X-ray diffraction and energy dispersive x-ray measurements have indicated that these films contain exclusively a phase with a chalcopyrite structure. The morphology, grain distributions and composition of the CIGSe films were studied and compared for x = 0.5 and x = 0.75. The optical studies have shown that the films are highly absorbing (7 x 10(4) cm(-1)). The absorption edge is shifted to high photon energies when the gallium concentration is increased. After selenization, the bandgaps increase from 1.00 eV to 1. 18 eV for x = 0.75 and from 1.16 eV to 1.28 eV for x = 0.5.