Abstract: J-V characteristics of Cu(In1-xGax)Se2 (CIGS) thin film solar cells are measured and analyzed.The diode saturation current density J0,diode quality factor A,series resistance Rs and shunt resistance rsh are deduced using Matlab.The calculated results coincide with the measurement very well.A CIGS cell produced in our laboratories is characterized at different illumination intensities.The calculated characteristic parameters are plotted with the irradiance.The shunt resistance rsh decreases as illumination increases.The increased shunt resistance is most likely one of the reasons for the better performance of CIGS solar cells under week illumination.

Key words: Cu(In1-xGax)Se2, solar cells, shunt resistance, grain boundary barrier, weak illumination