Fabrication of graded Cu(InGa)Se2 films by inline evaporation

An inline evaporation system for depositing Cu(InGa)Se₂ films from elemental sources was characterized. The system demonstrated reproducibly good deposition uniformity and device performance for translation speeds ranging from 1 to 2.5 inches/min. A source effusion model predicting film thickness, composition, and compositional gradients was developed and tested. The effusion model was reasonably successful in predicting measured film characteristics. The model can be further improved by a more accurate description of the flux profiles. In addition, effusion in the transitional flow regime and the possibility of Ga-ln interdiffusion need to be explored. Such an improved model would be a valuable tool for the design and development of commercial scale systems, as well as for improved efficiency and flexibility in manufacturing