Comparison of amorphous InZnO and polycrystalline ZnO:Al conductive layers for CIGS solar cells

We investigated the optical and electrical properties of amorphous InZnO (IZO) as a potential replacement of Al-doped ZnO (AZO) conducting window layer for CuInGaSe₂ (CIGS) solar cells. The device performance of CIGS devices with IZO of different thickness and sheet resistance was compared with that of CIGS standard devices with AZO. The results show that the optical and electrical properties of IZO were affected by deposition conditions, especially by the oxygen concentration, and thickness. Initial results on the CIGS solar cells showed that devices with IZO yield cell efficiencies comparable to that of the devices with standard AZO, when the sheet resistance of IZO was close to that of AZO.