Real time investigations of the influence of sodium on the properties of Cu poor prepared CuInS2 thin films

Abstract The influence of sodium on the growth path and the properties of Cu-poor prepared CuInS 2 (CIS) thin films is investigated. In situ experiments of X-ray diffraction and Raman spectroscopy reveal a different growth path when sodium is incorporated. A delay of the CIS formation has been found as well as a different contribution of the resulting phases in the layer like the In–S alloy is now supposed to be located nearer the surface. Sodium doping results in a remarkable increase in the lateral conductivity and the cell efficiency of CuInS 2 based solar cells.