F-doped CdO thin films deposited by spray pyrolysis

Thin films of CdO were prepared by spray pyrolysis using cadmium acetate as the Cd source. The films were intentionally doped with fluorine by adding NH4F in the solution. The substrate temperature was varied in the range fro m 170 to 290 degrees C while keeping the other,deposition parameters consta nt, except the NH4F concentration in the solution, which was varied up to 8 wt%. The structural; optical, and electrical properties of the films were studied in order to obtain, under our experimental conditions, optimal valu es for the NH4F concentration and substrate temperature. We show that the b est deposition conditions for a photovoltaic application of the films are s ubstrate temperature T-s = 210 degrees C and NH4F concentration around 4%.