Research Article

Cu(In,Ga)Se2 Thin Films Codoped with Sodium and Bismuth Ions for the Use in the Solar Cells

Figure 4

Current-voltage characteristics of Cu(In,Ga)Se2 films doped with (a) absence of dopants, (b) sodium ions, (c) bismuth ions, and (d) sodium ions and bismuth ions upon heating at 500°C for 30 min.