NEW APPROACHES TO OBTAIN CUIN1-XGAXSE2 THIN-FILMS BY COMBINING ELECTRODEPOSITED AND EVAPORATED PRECURSORS

CuIn1-xGaxSe2 thin films were obtained from a combination of Cu-Se ele ctrodeposited and In and/or Ga evaporated precursors, by heating in se lenium vapor atmosphere. The compound formation processes were studied as a function of three variables: (1) the precursors deposition seque nce, (2) the x = Ga/(In + Ga) film ratio, and (3) the annealing temper ature. X-ray diffraction analysis have shown that after 500 degrees C annealing, single-composition alloy thin films were obtained from the different precursor sequences. For sample temperatures below 500 degre es C, structural data have established that different reaction pathway s have led to the final quaternary compound formation, depending on th e deposition sequence. Alloying processes are enhanced in those arrang ements that favor binary selenide formation. Atomic force microscopy i mages have shown that grain size and surface roughness decrease as the Ga/(ln + Ga) ratio increases in the single-composition alloy thin fil ms. (C) 1998 Elsevier Science S.A. All rights reserved.