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

Figure 3

Atomic force micrographs 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.

(a)

(b)

(c)

(d)