Comparison of Material Properties of CuInSe2Films Produced by Reaction of Metallic Alloys to H2Se/Ar and Elemental Se Vapour

Abstract

In this study, CuInSe₂thin films were produced by the reaction of identical precursors toelemental Se vapour and H₂Se/Ar gas. In order to compare the respective growth processes, the reaction temperature was varied between 300°C and 600°C, while all other parameters were kept constant. For a given set of experimental parameters, significant differences were observed in terms of crystalline quality and in-depth compositional uniformity. At low selenization temperatures below 400°C, the reaction process was incomplete, irrespective of the selenization process considered. Reaction of precursors to H₂Se/Ar at temperatures above 400°C (for 40 min), produced fully reacted films with uniform and dense surface morphologies and a high degree of in-depth compositional uniformity. Under similar conditions, Se vapour treated samples had nonuniform surface morphologies with an associated relatively large variation in the Cu/In atomic ratio and Se concentration through the depth of the samples. This comparative study identifies the important differences between the two reactive processes and the advantages in using H₂Se/Ar as a chalcogenide source.