Structure, morphology and optical properties of CuInS2 thin films prepared by modulated flux deposition

The structure, morphology and optical properties of copper indium sulfide thin films prepared by a novel modulated flux deposition procedure have been investigated for layers from 200 to 400 nm thickness. These polycrystalline CuInS2 films grown onto glass substrates showed CuAu-like structure, similar to epitaxial CuInS2 films grown onto monocrystalline substrates, and direct band gap values Eg=1.52–1.55 eV, optimum for single-junction photovoltaic applications. The increase in the layer thickness leads to growth of the average crystallite size and increases slightly the surface roughness and the absorption coefficient.