Current Photovoltaic Research ISSN:2288-3274(Print) 2508-125X(Online)

CIGS solar cell consisted of various films. In this research, we investigated electrode materials in Cu(In,Ga)Se₂ (CIGS) cells, including Al-doped ZnO (ZnO:Al), intrinsic ZnO (i-ZnO), and Al films. The sputtered ZnO:Al film with a sputtering power at 200W showed the lowest series resistance and highest cell efficiency. The electrical resistivity of the 200-W sputtered ZnO:Al film was 5.2x10 ^-4 Ω·cm by the rapid thermal annealing at 200°C for 1 min. The electrical resistivity of i-ZnO was not measurable due to its high resistance. But the optical transmittance was highest with less oxygen supply and high efficiency cell was achieved with O₂/(Ar+O₂) ratio was 1% due to the increase of short-circuit current. No significant change in the cell performance by inserting a Ni layer between Al and ZnO:Al films was observed.