A TEM Study of the Microstructure Evolution of Cu(In,Ga)Se_2 Films from Cu-Rich to In-Rich

摘要

The microstructure of Cu(In,Ga)Se_2 (CIGS) films with compositions ranging from Cu-rich to In-rich was investigated by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). We found that the Cu-rich samples have larger grain sizes than the In-rich sample. In the Cu-rich samples, sub-interfaces were observed. The two sides of the sub-interfaces were found to have different Cu concentration. In the In-rich sample, Ga inhomogeneity across grains was observed.