Effect of Reduced Cu(InGa)(SeS) Thickness Using Three-Step H Se/Ar/H S Reaction of Cu-In-Ga Metal Precursor

Cu(In,Ga)(Se,S) 2 (CIGSS) absorbers with thicknesses from 1.9 to 0.25 μm have been grown using a three-step selenization/Ar-anneal/sulfization reaction of Cu-In-Ga metal precursors. Material characterization revealed changes in orientation, apparent grain size, and formation of voids at the Mo/CIGSS interface with reduced thickness. Even with absorber thickness decreased to 0.25 μm and lateral compositional nonuniformity, V OC and fill factor were nearly sustained, while J SC decreased due to incomplete absorption. With the 0.25-μm-thick absorber layer, an efficiency of 9.1% (without AR coating) with V OC = 612 mV, J SC = 21.0 mA/cm 2 , and FF = 71.1% was obtained.