Photoacoustic spectroscopy of sprayed CuGaxIn1-xSe2 thin films

CuGa(x)ln(1-x)Se(2) thin films have been produced using spray-pyrolysis. Th e lavers were deposited onto Mo-coated soda-lime glass at a substrate tempe rature of 623 K, and the gallium content of the layers varied. The layers w ere investigated using photoacoustic spectroscopy. The normalised photoacou stic spectra of CuGa(x)ln(1-x)Se(2) films with x = 0, 0.2, 0.4 and 0.5 show ed a sudden fall in the photoacoustic signal at photon energies of 0.99, 1. 15, 1.27 and 1.36 eV, respectively, which correspond to the respective dire ct energy band gaps of these films. The photoacoustic spectra also showed p eaks at 0.75, 0.78, 0.82, 0.86 and 0.88 eV, respectively, in the sub-band g ap region, which have been attributed to the defect states within these fil ms. (C) 2001 Elsevier Science B.V. All rights reserved.