Coupled Process/Device Modeling and Point Defect Engineering of Cu(In,Ga)Se₂ Solar Cells

Point defects directly impact solar cell device performance by limiting the carrier lifetime. In this work, density functional theory calculations are first used to determine the formation energy and diffusion energy barriers of dominant defects in Cu(In,Ga)Se-2. Next, continuum reaction-diffusion models are developed to analyze the redistribution of defects during manufacturing processes. We estimate defect capture cross sections using a first-principles-based approach. These cross sections are combined with our calculated defect profiles and trap energy levels to parameterize a Shockley-Read-Hall recombination model, which we implement into a device simulator to predict carrier lifetimes and device performance. In that way, a predictive technology computer aided design model is built to predict and optimize the performance of Cu(In,Ga)Se-2 solar cells.