CIGS absorbing layers prepared by RF magnetron sputtering from a single quaternary target

Cu(In1−xGax)Se2 (CIGS) thin films were prepared by RF magnetron sputtering from a single quaternary target at multiple processing parameters. The structural, compositional, and electrical properties of the as-deposited films were systematically investigated by XRD, Raman, SEM, and Hall effects analysis. The results demonstrate that by adjusting the processing parameters, the CIGS thin films with a preferential orientation along the (112) direction which exhibited single chalcopyrite phase were obtained. The films deposited at relatively higher substrate temperature, sputtering power, and Ar pressure exhibited favorable stoichiometric ratio (Cu/(In+Ga):0.8-0.9 and Ga/(In+Ga):0.25-0.36) with grain size of about 1-1.5 µm, and desirable electrical properties with p-type carrier concentration of 1016−1017 cm−3 and carrier mobility of 10-60 cm2/Vs. The CIGS layers are expected to fabricate high efficiency thin film solar cells.