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 NH 4 F in the solution. The substrate temperature was varied in the range from 170 to 290°C while keeping the other deposition parameters constant, except the NH 4 F 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 values for the NH 4 F concentration and substrate temperature. We show that the best deposition conditions for a photovoltaic application of the films are substrate temperature T s = 210 °C and NH 4 F concentration around 4%.