Changes in the dominant recombination mechanisms of polycrystalline Cu(In,Ga)Se2 occurring during growth

Abstract
The changes in dominant recombination mechanisms of Cu(In,Ga)Se2 thin films grown from (In,Ga)2Se3 precursors are investigated using energy- and time-resolved photoluminescence. The results are analyzed with a rate-equation analysis and correlated with n/p diode measurements on processed devices. The experimental results quantify a change in the dominant radiative process and an improvement in the underlying material quality. These observations support a growth model incorporating changes in the dominant defect states and recombination mechanisms during this final stage of the growth process. Additionally, evidence is presented that supports the passivation of near-surface recombination sites by CdS.