Thinning of CIGS solar cells: Part II: Cell characterizations

In this paper, the influence of reducing the thickness of the CIGSe absorber layer by bromine etching from 2.5 μm to 0.5 μm on electrical and optical solar cell properties is addressed. We observe a decrease in efficiency which is mainly caused by a reduced short circuit current, whereas the fill factor and the open circuit voltage are stable. Even without deliberate light trapping or anti-reflection coating, an efficiency of 10.3% is obtained for a 0.5 μm thick CIGSe absorber. A smoothing of the absorber surface is observed during the etching, its influence on the cell parameters will be discussed.