Raman spectroscopy of CuIn1 − xGaxSe2 for in-situ monitoring of the composition ratio

Metal organic vapor deposition (MOCVD) is a well known method for preparing high quality and large area CuIn1 − xGaxSe2 (CIGS) absorber layers. Some in-situ non-contact monitoring systems are needed when CIGS absorber layers are manufactured in industry. In this study, CuInSe2 (CIS) and CIGS thin films with different composition ratios, [Cu]/[In + Ga], were prepared by MOCVD using [Me2In(μ-SeMe)]2, hexafluoroacetylacetonate Cu(I) (3,3-dimethyl-1-butene), trimethyl gallium and dimethyle diselenide as the In–Se single source, Cu, Ga and Se precursors, respectively. The Raman shift spectra of the films with various composition ratios were analyzed to produce a basic algorithm that can determine the composition ratios of CIS and CIGS thin films indirectly.