Quality assessment of CuInS2-based solar cells by Raman scattering

In this work spectroscopic features of the Raman $A_1$ mode of ${\mathrm{CuInS}}_2$ thin films are investigated. A broadening of the $A_1$ mode in combination with an asymmetry towards larger wave numbers is observed. The comparison with parameters of the solar cells formed out of these thin films reveal a direct correlation between the linewidth of the $A_1$ mode and the solar cell data. A significant decrease of open circuit voltage and fill factor of the cells is found for linewidths larger than 3.8 cm⁻¹. For linewidths smaller than 3.8 cm⁻¹, a saturated behavior of the solar cell parameters is observed. This saturation indicates other origins of performance limitation to be present in ${\mathrm{CuInS}}_2$ based devices.