Electrodeposition of CuInxGa1-xSe2 thin films

CuInxGa1-xSe2 (CIGS) polycrystalline thin films with various Ga to In ratio s were grown using a new two-step electrodeposition process. This process i nvolves the electrodeposition of a Cu-Ga precursor film onto a molybdenum s ubstrate, followed by the electrodeposition of a Cu-In-Se thin him. The res ulting CuGa/CuInSe bilayer is then annealed at 600 degrees C for 60 min in flowing Argon to form a CIGS thin film. The individual precursor films and subsequent CIGS films were characterized by X-ray diffraction, scanning ele ctron microscopy, energy dispersive spectroscopy and Auger electron spectro scopy. The as-deposited precursor-films were found to be crystalline with a crystal structure matching that of CuGa2. The annealed bi-layers were foun d to have the same basic chalcopyrite structure of CuInSe2, but with peak s hifts due to the Ga incorporation. Energy dispersive spectroscopy results s how that the observed shifts correlate to the composition of the films. (C) 1999 Elsevier Science B.V. All rights reserved.